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AN
INTRODUCTION
TO
THE MODERN CLASSIFICATION
OF
INSECTS;
FOUNDED ON
THE NATURAL HABITS AND CORRESPONDING ORGANISATION
OF
THE DIFFERENT FAMILIES.
By J. O. WESTWOOD, F.L.S.
HON. MEM. LIT. HIST. SOC. QUEBEC ; MEM. SOC. CjES. NAT. MOSCOW PHYSIOGR. SOC. LUND ; SOC. ROY. SCIENC. LILLE ; SOC. HIST. NAT. MAURITIUS ; SOC. CUVIER. PARIS ;
PLIN. SOC. EDINBURGH ; LIT. PHIL. NAT. HIST. SOC. BELFAST, RICHMOND, SHEFFIELD ; MEM. SOC. ENTOMOL. DE FRANCE ; SECRETARY ENT. SOC. LONDON, ETC.
“ Empirici , formica more, congerunt tantum et utuntur: rationales, aranearum more, telas ex se conficiunt : apis vero ratio media est, quae materiam ex floribus horti et agri elicit ; sed tamen earn propria facultate vertit et digerit.” — Bacon, Nov. Org. lib. i. aph. 95.
IN TWO VOLUMES.
VOL. II.
LONDON:
LONGMAN, ORME, BROWN, GREEN, AND LONGMANS,
PATERNOSTER-ROW.
1840
London:
Printed by A. SponiswooDis, New-Strcct-Square.
CONTENTS
OF
THE SECOND VOLUME.
Page
|
THYSANOPTERA |
- |
1 |
|
ThRIPIDjE |
- |
5 |
|
NEUROPTERA |
- |
5 |
|
TER3IITID/E |
- |
1 1 |
|
PsOCIDiE |
- |
17 |
|
Perlid.e |
- |
20 |
|
Ephemerid^: |
- |
24 |
|
LiBELLULIDjE |
- |
35 |
|
Myrmeleonidte |
- |
41 |
|
HE3IEROBIIDiE |
- |
46 |
|
SlALID/E |
- |
49 |
|
Panorpid.e |
- |
52 |
|
Raphidiid^e |
- |
55 |
|
MANTISPIDiE |
- |
58 |
|
TR1CHOPTERA |
- |
60 |
|
Phryganeid^e |
- |
72 |
|
HYMENOPTERA |
- |
72 |
|
Terebrantia |
- |
88 |
|
Phytiphaga |
- |
89 |
|
TENTHREDINIDiE |
- |
90 |
|
UROCERID/E |
- |
114 |
|
Entomophaga |
- |
122 |
|
CYNIPIDiE |
- |
125 |
|
EVANIID/E |
- |
133 |
|
IcHNEUMONID/E |
- |
136 |
|
CHALCIDID/E |
- |
154 |
|
PROCTOTRUPIDiE |
- |
167 |
|
Chrysipid^e |
- |
174 |
|
Aculeata |
- |
180 |
|
P roe clones |
- |
184 |
|
Insectivora |
- |
185 |
|
CRABRONID2E |
- |
190 |
|
LaRRID/E |
- |
200 |
|
Bembecidas |
_ |
201 |
Page
SphegiDjE - . 203
Scoliid^e - _ 209
Mutillidje - - 213
Sodales (Philopona K .) - 217
FormiciDjE - . 217
Diplopteryga - - 236
Eumenid/e - - 239
V ESPIDiE - - 244
Mellifera - -252
^NDRENID/E - - 263
ApiDiE - 267
Social Bees - - 278
STREPSIPTERA - - 287
Stylopid/e - _ 306
LEPIDOPTERA - . 306
Classification of Order - 324 Ilhopalocera - - 330
Papilionid^e - . 347
HELICONlIDiE - - 351
Nymphalid.e - - 353
Erycinidte - - 357
LyCjEnidte - - 358
Hesperiid^e - - 360
Heterocera - - 361
Sphingid/e - - 364
Uraniid/e - - 369
Anthrocerid/E - - 371
/Egeriid.e - - 373
Hepialida: - - 375
Bomb yci D/E - - 379
ARCTIIDiE - - 384
Lithosiid/E - - 390
Noctuidve - - 391
Geometrid.e - - 395
a 2
iv
CONTENTS.
Page
Pyralide - - 398
ToRTRICIDE - - 401
Yponomeutide - - 404
Tineide - - 409
Alucitide - - 413
HOMOPTERA - - 414
Trimera - - - 419
Cicadide - - 420
Fulgoride - - 427
Cercopide - - 431
Dimera - - - 434
Psyllide - - 435
Aphide - - 437
Aleyrodide - - 442
Monomera - - 444
Coccide - - 444
HETEROPTERA - - 450
Hydrocorisa - - 457
Notonectide - - 458
Nepide - - 459
Aurocorisa - - 462
Galgulide - - 463
Acanthiide - - 465
HydrometriDjE - - 467
Reduviide - - 470
CimicidjE - - 474
Tingide - - 477
Capside - - 479
Lygeide - - 480
Coreide - - 482
Scutelleride - - 485
Page
APHANIPTERA - - 489
Pulicide - - 489
DIPPER A ( - - 495
Neraocera - - 506
Culicide - - 507
Tipulide - - 513
Brachocera - - 529
Stratiomide - - 531
Beride - - 533
Ccenomyide - - 535
Tabanide - - 538
Bomb yli ide - - 542
Anthracide - - 543
Acroceride - - 545
Empide - - 546
Tachydromiide - - 547
Hybotide - - 548
Asilide - - 548
Mydaside - - 549
Tiierevide - - 550
Leptide - - 551
Doliciiopide - - 552
Scenopinide - - 553
Syrphide - - 556
Conopside - - 560
Muscide - - 561
(Estride - - 575
Pupipara - - 580
Hipfoboscide - - 581
Nycteribiide - - 585
ALPHABETICAL INDEX
TO
THE FAMILIES.
Acanthiidae, ii. 465. Achetidae, i. 439. Acroceridae, ii. 545. iEgeriidae, ii. 373. Agathidiid*, i. 130. Aleyrodidae, ii. 442. Alucitidae, ii. 413. Andrenidae, ii. 263. Anoplognatliidae, i. 215. Anthracidae, ii. 543. Anthroceridae, ii. 371. Aphidae, ii. 437. Aphodiidae, i. 207. Apidae, ii. 267.
Arctiidas, ii. 384. Asilidae, ii. 548. Attelabidae, i. 333.
Bembecidae, ii. 201. Beridae, ii. 533. Blapsidae, i. 320. Blattidae, i. 414. Bombycidae, ii. 379. Bombyliidae, ii. 542. Bostrichidae, i. 277. Bruchidas, i. 326. Buprestidae, i. 226. Byrrhidse, i. 178.
Caenomyidae, ii. 535. Cantliaridae, i. 295. Capsidae, ii. 479. Carabidae, i. 57. CassididaB, i. 376. Cebrionidae, i. 243. Cerambycidae, i. 362. Cercopidae, ii. 431. Cetoniidae, i. 221. Chalcididae, ii. 154. Chrysididae, ii. 174. Chrysomelidae, i. 385. Cicadidae, ii. 420. Cicindelidae, i. 47. Cimicidae, ii. 474.
Cistelidae, i. 309. Cleridae, i. 261 . Coccidae, ii. 444. Coccinellidae, i. 395. Conopsidae, ii. 560. Coreidae, ii. 482. CrabronidaB, ii. ] 90. Crioceridae, i. 372. Culicidae, ii. 507. Curculionidae, i. 338. Cynipidae, ii. 125. CyphonidaB, i. 246.
Dermestidae, i. 155. Diaperidae, i. 314. Dolichopidae, ii. 552. Dynastidae, i. 210. Dytieidae, i. 95.
Elateridae, i. 235. Empidae, ii. 546. Endomychidae, i. 393. Engidae, i. 143. Ephemeridae, ii. 24. Erotylidae, i. 391. Erycinidae, ii. 357. Eucnemidae, i. 232. Eumenidae, ii. 239. Evaniidae, ii. 133.
Forficulidae, i. 398. Formicidae, ii. 217. Fulgoridae, ii. 427.
Galerucidae, i. 381. Galgulidae, ii. 463. Geometridae, ii. 395. Geotrupidae, i. 201. Glaphyridae, i. 220. Gryllidae, i. 450. Gyrinidae, i. 105.
Heliconiidae, ii. 351. Ilelophoridae, i. 120.
A 3
Helopidae, i. 311. Hemerobiidae, ii. 46. HepialidaB, ii. 375. Hesperiidae, ii. 360. Heteroceridas, i. 113. Flippoboscidae, ii. 581. Flisterida?, i. 181. HoriidaB, i. 291. Hybotidae, ii. 548. Hydrometridae, ii. 467. Hydrophilidae, i. 122.
Ichneumonidae, ii. 136.
Laigriidae, i. 289. Lampyridae, i. 246. Larridae, ii. 200. Leptidae, ii. 551. Lepturidae, i. 369. Libellulidae, ii. 35. Lithosiidae, ii. 390. Locustidae, i. 456. Lucanidae, i. 185. Lycaenidae, ii. 358. Lygaeidae, ii. 480. Lymexylonidae, i. 273.
Mantidae, i. 424. Mantispidas, ii. 58. Melandryid®, i. 305. Melolontliidae, i. 216. Melyridae, i. 258. Mordellidae, i. 292. Muscidae, ii. 561. Mutillidao, ii. 213. Mycetophagidae, i. 152. Mydasidae, ii. 549. Myrmeleonidae, ii. 41.
Nepidae, ii. 459. Nitidulidas, i. 140. Noctuidae, ii. 391 . Notonectidae, ii. 458. Notoxidae, i. 286. Nycteribiidae, ii. 585.
vi
Nymplialida, ii. 353.
CEdemerida, i. 304. (Estrida, ii. 575.
Panorpida, ii. 52. Papilionida, ii. 347. Parnida, i. 115. Paussida, i. 150. Perlida, ii. 20. Phasmida, i. 430. Phryganeida, ii. GO. Pimeliidae, i. 323. Prionida, i. 359. Proctotrupida, ii. 167. Psocida, ii. 17. Psyllida, ii. 435. Ptinida, i. 268. Pulicida, ii. 489. Pyralida, ii. 398. Pyrochvoida, i. 287.
INDEX TO TI1E FAMILIES.
Rapliidiida?, ii. 55. Reduviidae, ii. 470. Rutelidae, i. 213.
Salpingida, i. 304. Scaphidiidae, i. 134. Scarabaidae, i. 203. Scenopinidac, ii. 553. Scoliida, ii. 209.
Scolytidae, i. 350. Scutelleridee, ii. 485. Scydmanida, i. 279. Sialida, ii. 49.
Silphida, i. 135. Spharidiida, i. 128. Sphegida, ii. 203. Sphingida, ii. 364. Staphylinida, i. 162. Stratiomida, ii. 531. Stylopida, ii. 306. Syrphida, ii, 556.
Tabanida, ii. 538. Tacbydromiida, ii. 547. Telepborida, i. 255. Tenebrionida, i. 316. Tenthredinida, ii. 90. Termitida, ii. 11. Therevida, ii. 550. Thripida, ii. 1. Tineida, ii. 409. Tingida, ii. 477. Tipulida, ii. 513. Tortricida, ii. 401 . Trogida, i. 208.
Uraniida, ii. 369. Urocerida, ii. 114.
Vespida, ii. 244.
Yponomcutida, ii. 401.
ERRATA ET ADDENDA.
VOL. I.
Page 1. line 13. for “ regarded Mr. MacLeav” read “ regarded by Mr. Mae- Leay.”
10. line 1. dele “ upper lip.”
21. note *, The name Dermaptera was first used by De Geer himself for the mandibulated Hemiptera, which Olivier subsequently, named Orthoptera. Leach improperly retained the latter name, and separated the Forficulida? therefrom, for. which with equal impropriety, he retained the name of Dermaptera. Retzius, in his commentary on De Geer, confused these names, by giving the mandibulated Hemiptera under the name of Hemiptera, and a portion of the haustellated ones (Cimex, &c. ) under that of Dermaptera. The latter name ought certainly to supersede Olivier’s name, Orthoptera.
31. line 1. add: Hope. The Coleopterist’s Manual. Parts 1, 2, 3. Lon¬ don, 8vo. 1837 — 1840.
line 10. add: Stephens. Manual of British Coleoptera. London, 1vol. 8vo. 1839.
Spry and Shuckard. British Coleoptera delineated ; in parts, 8vo. 1839 — .
Shuckard. Elements of British Entomology. Part 1., 1839.
47. Messrs. Kirby and Spence, in a subsequent edition of their In -
traduction , give the name Eutrechina instead of Eupodina.
86. See Entomol. Mag. vol. i. p. 92. for an account of the habits of
Broscus.
95. line 9. for “ Zool. Journ." read “ Zool. Misc."
114. line 24. for “ Helerocerus” read “ Heterocerus. ”
151. line 12. Mr. Miers has communicated to me a species of Cerapterus, cap¬ tured in the neighbourhood of Rio Janeiro, forming a dis¬ tinct subgenus.
162. note *, add: Erickson. Genera et Species Staphylinorum. 8vo. 1839.
192. note*, add: Schmidt's Review of German Aphodii in Germar’s Zeitschr.
f. d. Entomol. No. 3.
196. M. V. Audouin has communicated to me an instance of the de¬
struction of the larvae of Melolontha vulgaris by Gordii.
235. note *, add : Germar. Distribution of Elateridae, in his Zeitschr. f. d.
Entomol. No. 2.
332. line 35. for “ exo” read “ exotic.”
333. line 18. for “fig. 40. 22.” read “40. 23.”
336. line^ 5. M. Huber has published an extended memoir on the habits of Attelabus in the Memoirs of the Academy of Geneva, vol. viii. part 2.
346. line 28. for “ this disease” read “ curing this disease.”
ERRATA ET ADDENDA.
407. Since the publication of the sheets relative to the Orthoptera,
two works especially devoted to that order have been pub¬ lished ; namely, the second part of the second volume of Bur- meister’s Handbuch der Entomologie, 1 838, and Histoire Natu- relle des Insectes Orthopteres, 1839, by M. Serville. In these works numerous new genera are proposed, chiefly founded upon exotic species, under distinct names. Burmeister has subsequently reviewed their synonymy in the third part of Germar’s Zeitschrift fur d. Entomologie.
428. note *, line 2. for “ Blattidse ” read “ Mantida?.”
451. fg. 55. 16. The short transverse lines at the tips of the antennae indicate the extremities of these organs to have been cut off.
VOL. II.
e 5. add as note : * Bjbihogr. Refer, to the Neuroptera.
Say , in Goodman’s Western Quarterly Reporter, vol. 2. 8vo. 1823. (13 sp. Neuropt. collected in the Expedition to the Rocky Mountains.) — Ditto, Descriptions of new North American Neuroptera (not yet published. See his Life).
Burmeister. Hand. d. Entomologie, vol. ii. part 2. p. 2. (Neuroptera) 1839.
Stephens, Curtis, Latreille, fyc.
15. M. Lacordaire has published some original observations on the
different kinds of individuals composing the species of Termi- tidse in his Introduction to the Natural History of Insects.
17. line 18. 1 have recently discovered an apterous species of this family, possessing more than twenty-five joints in the antennae, and 3-jointed tarsi.
25. note *, The existence of the anomalous character of an additional pair of eyes, placed on pillars, is not confined to the males of a single species, or even subgenus of Ephemeridre. I have this day (May 14. 1840) taken both sexes of the two-winged species, figured by Mr. Stephens under the name of Cloeon dipterum, and find that the males possess this character, and are, in co¬ lour, quite unlike the females. Neither Leach nor Stephens have noticed the sexual characters of Cloeon. The species figured by Reaumur, possessing two similar additional pedun¬ culated eyes (tom. iv. pi. 19. fig. 3.), evidently belongs, from his accurate description of the very minute hind wings, to my subgenus Bracliyphlebia. Burmeister ( Handb. vol. ii. p. 798.) gives E. bioculata L., as the male of E. diptera L.
45. Mr. Swainson has published a figure of the larva of Ascalaphus
MacLeayanus Guild, in his volume on the Habits and In¬ stincts of Animals, p.29. It differs from my fig. 63. 20. and from G u il ding's description, in having only nine filamentous processes on each side.
51 . Dr. Buckland has described a remarkable fossil insect, of which
ERRATA ET ADDENDA.
IX
a wing only has been discovered, under the name of Heinero- bioides giganteus (Proceed. Geol. Soc. June 6. 1838); it having appeared to me to possess greater affinities with the wing of Hemerobius than any other existing insects.
72. line 35. for “apud” read “ Apum.”
74. line 4. Say ( Boston Journ. of Nat. Hist. vol. i. no. 4.) describes a section of Lyrops with only one ocellus.
76. note *, The Baron de Romand has had the kindness to send me a copy of a memoir on the variations in the nervures of the Hymen- opterous wings, recently published by him privately, and illus¬ trated by numerous figures.
82. line 10. and 22. for “ cuckoo flies” read “ ichneumon flies.”
84. et passim, for “ Bethyllus ” read “ Bethylus.”
88. The valuable classification of the Hymenoptera, published by
Mr. Haliday, reached me too late to be noticed in the text. It is partially noticed in the Generic Synopsis.
114. line 18. for “ Siricidae ” read “ Uroceridae.”
119. and 121. Saint Fargeau, in his Hist. Nat. Hymenopt. p. 5. notes 1, 2, and 3., has re- stated his opinion of the parasitic nature of Urocerus and Xiphydria. The German entomologists, who have such ample opportunities for studying the habits of these insects, describe them as Xylophagous, and the structure of their jaws confirms such statement.
123. line 13. for “ top” read “tip.”
line 33. I have used the name of Entomophaga instead of Latreille’s Pu- pivora, which is inapplicable to the majority of the species.
125. note *, add : Hartig. Revision of the fam. Cynipidae (divided into twenty-
one Genera) in Germar’s Zeitschrift, f. d. Entomol. No. 3,
127. line 20. for “ 73. c.” read “ 73. 2 2. c.”
143. line 8. M. Wesmael {Ann. Soc. Ent. de France, 1837, pt. 3.) describes the habits of a Bracon, which attacks Scolytus.* I took one of the species of this genus in the Parc de Belle Vue, near Paris, on felled trees infested by Scolyti, and which M. Au- douin also informed me was its parasite.
145. line 25. Moses Harris states that “on a moderate computation,” there
might be 20,000 minute Ichneumons found by him in a single chrysalis of a goat moth (Aurelian, pi. 23.).
146. line 23. bis, for “ its ” read “ their.”
M. Schiodte has figured some Ichneumonidae in Guerin’s Maya - zin de Zoologie, which exhibit similar peculiarities in the mode of exclusion of the eggs.
148. line 36. for “ both at the top and bottom” read “ either at the top or bottom.”
164. line 34. My monograph on Leucospis has been published in the second part of Germar’s Zeitschrift, f. d. Entomologie.
169. Mr. Curtis, in his dissections of the ovipositor of Proctotrupes,
noticed, in addition to the parts figured by me (fg. 78. 7 ), an elongated membranous plate. I had also noticed this in seve¬ ral of the females of this genus which I had dissected, but
X
ERRATA ET ADDENDA.
concluded it was some extraneous matter or the lining of the other parts.
Page 171. line 17. for “ an inch ” read “ a line.”
173. line 17. for <{ Diapria,” read “ Diapria),”.
174. note*, add: Klug, in Proceed. Roy. Acad. Berlin, 10 Jan., 1839 (and
in Annals of Natural History).
1S4. line 24. after Sodales add (Philopona Kirby, F. B. Amer . )
line 26. after Diploptera add (Diplopteryga K., F. B. Amer.')
207. line 9. and following.’ S. S. Saunders, Esq. has transmitted to his cousin W. W. Saunders, Esq., from Albania, the mud nests made by Pelopaeus spirifex ; and Mr. Uoubleday mentions that the American species of that genus are well known in the United States under the name of “ mud dabs,” from their nests resembling a patch of mud.
212. line 34. fig. 84. 1 1. represents the labium of Sapyga punctata.
216. line 1. Mr. Shuckard has published ( Annals of Nat. Hist. May, 1840) the commencement of a monograph on the family (as he terms it) Dorylidaj, in which he describes.' two new genera and nu¬ merous species; and has endeavoured to prove, 1. that these insects are more nearly allied to the Mutillidae, and are conse¬ quently not furnished with neuters ; 2. that they are parasites ; and 3. that my] genus Typhlopone ( fig. 86. 17 — 20.) is the female of the genus Labidus. I propose to make some remarks on this memoir, not coinciding with several of these opinions.
233. line 31. Mr. Swainson, unacquainted with these observations, has pub¬
lished an account of the habits of a Brazilian species of Ama¬ zon ant, which makes slaves of the neuters of other species, but which it carries off in the perfect neuter state, and not whilst larvae or pupae. ( On the Habits and Instincts of Animals , p. 334.)
234. line 9. Mr. Swainson, in like manner, unacquainted with these observa¬
tions, has detailed, as a new fact, the circumstance of the ants of Brazil milking the Membracides of that region in conse¬ quence of the absence of the Aphides. ( Habits of Animals, p. 338.)
241. line 24. and 240. note*. M. Dufour’s memoir has been published in the Annales des Sci. Nat. for Jan. 1839, accompanied by sup¬ plemental observations by M. Audouin. In these memoirs four distinct species are stated to form curved tubes at the mouths of their burrows in the sand. M. Audouin (like Mr. Shuckard), following M. Wesmael, considers the O. muraria, whose history is detailed by Reaumur (M£m. 6. pi. 26. f. 2.), as identical with Oplomerus spinipes. The O. rubicola L. D. is closely allied to the O. laevipes of Shk.
253. note *, add : Herrick Schaffer on the European Nomadae in Germar’s
Zeitschr. f. d. Entomol. tom. ii. pt. l.°
Jardine's Naturalist's Library, Volume on Bees, containing figures and descriptions of some new exotic species by myself.
ERRATA ET ADDENDA.
XI
Page 257. note *, line 4. for “Jig. 89. 19.” read “ 89. 9.”
.‘347. line 12. for “ Ileterocera” read “ Rhopalocera. ”
line 20. for “ Thysanumorpha ” read “ Thysanuromorplia. ”
368. line 8. See also Nordmann, in Rev. Z ool. Soc. Cuvierr. Aug. 1838.
437. line 10. Mr. Hoy has given (Linn. Trans, vol. ii. p.354.) an account of the production of Chermes graminis (which is evidently iden¬ tical with Livia Juncorum) from Juncus articulatus $ of Lin¬ naeus, by whom it was supposed to be a viviparous variety.
441. line 1. for “species agreeing” read “ species nearly agreeing. ”
2. for “ Lachnus lanigerus” read “ Eriosoma lanigera.”
4, 5. dele “ which Mr. Haliday has conjectured is identical with Phylloxera.”
445. line 2. for “ Pseudoccus ” read “ Pseudococcus.”
535. line 16. Mr. Gosse, in the Canadian Naturalist, London, 1840, p. 199., has described and figured the pupa and imago of an American species of Ccenomyia, which he had observed amongst the grass, extricating itself from the pupa, which “ is large, and the hind segments have rings of spines ; its colour is chestnut- brown, and it much resembles that of a large moth. I have no doubt it is subterraneous in the pupa state.” I have followed Latreille, the founder of this genus, in writing the name Ca:- nomyia.
MODERN CLASSIFICATION
OF
INSECTS.
Order THYSANOPTERA Holiday .»
(Genus Thrips Linn.')
Char. Wings 4, alike, long, narrow, membranous, neither folded nor reticulated, with long ciliae, laid horizontally along the back when at rest.
Mouth with two setiform mandibles ; two triangular flat palpi- gerous (but not galeated) maxillae, and a palpigerous labium.
Tarsi, with two joints, vesiculose at the tip.
Pupa active, semi-complete.
The insects of this order {Jig- 57. l. Phlaeothrips coriacea Hal.?)
Fig. 57.
is long, linear, and depressed; the head {Jig. 57.2. upper side) is
* Bibliogr. Refer, to the Thysanoptera. (Thripidhs.) Holiday , in Entomol. Mag. vol. iii. and iv.
Schrank. Beitrage zur Naturgesch. 1776. Leipz.
Passerini, in Atti dell Acad. Georgofili. t. xii.
Vassali Eandi, in Mem. Acad. Turin, tom. xvi. p. 76.
Heeger. - ?
Linnaeus, Fubricius, He Geer , Geoffroy, Latreille.
VOL. II.
B
c2
MODERN CLASSIFICATION OF INSECTS.
oblong, narrower than thorax, without any distinct neck ; the eyes are large, coarsely granulated, and occupy its anterior lateral angles, besides which, there are ordinarily three ocelli between the eyes, and behind the antennae ; the underside of the head ( Jig . 57. 3.) is pro¬ longed into a kind of conical beak, which extends beneath the pro¬ sternum ; the antennae (Jig- 57. 7. and 57. 15. T. fasciata) are longer than the head, filiform, and apparently varying in the number of joints from five to nine, in consequence of the terminal joints being more or less firmly soldered together ; they are inserted in front of the head. The parts of the mouth, although constructed in the mandibulated and palpigerous form, unite into a short conical sucker, which does not ex¬ tend beyond the anterior coxae. The clypeus and labrum occupy the anterior part, the latter being linear-subconical, beneath the base of which arise a pair of horny setiform mandibles (Jig. 57. 4.), of which the base is dilated into a flattened plate in the species I have dis¬ sected. (Mr. Holiday described them as having a bulbous base, and, by their junction towards the tip, as forming a 2-valved syphon.) The maxillae (Jig- 57- 5. and 57. 13. T. fasciata) are flat, elongate-trian¬ gular, and pointed at the tip, without any apparent articulation, and with a 2 or 3-jointed palpus, arising on the outer edge near the middle ; there is no appearance of an outer lobe or galea. The labium (Jig. 57- 6.) is submembranaceous, and more or less attenu¬ ated in front; in some species the mentum is very distinct, and the labium is extended in front, between, and of equal length with, the palpi*; but in T. fasciata (Jig- 57- 14.) I could not perceive it to be prolonged beyond the base of those organs; the labial palpi are very short, and 2 or 3-jointed.
De Geer was the first author who noticed the existence of palpi in these insects. Latreille, also, described the maxillary pair, but re¬ garded the labial palpi as articulated lacinioe. He, moreover, over¬ looked the mandibles which were first observed by Strauss, who com¬ municated the discovery to Latreille ( Fam . Nat. p. 416.), who, however, seems to have been inclined to doubt their right to such a title, although admitting that, if they were really mandibles, they would form a very peculiar family in the order Orthoptera ; although
* “ Rostri vagina (including the maxilla? and labium), submembranacea ad basin lata et utrinque uni-palpigera (scil. the maxillary palpi), apice profunde tri- fida ; laciniis aeque longi.s, media acuta ; extends (scil. the labial palpi), subli- nearibus triarticulatis ; palpi (maxillary), brevissimi filiformes,” &c. Latr. Gen. 3. 171.
THYSANOPTERA. - THRIPIDiE.
3
l'ensemble de leur organisation ” appeared more allied to the Homoptera than the Orthoptera.*
The figures given above are the first which have yet been pub¬ lished of the parts of the mouth in detail of these curious insects.
The prothorax is large, depressed, and more or less narrowed in front, its hind part being broader than the head ; the meso- and meta¬ thorax are large, flat, and closely soldered together, the former being often the shorter, and transverse; the meso-scutellum is not a con¬ spicuous piece ; the four wings are nearly alike, the anterior pair {fig- 57- ll.) being rather larger than the posterior {Jig- 57- 12.) ; they are ordinarily narrow, membranous, and without nerves, crossing and resting horizontally upon the back, and furnished with long and deli¬ cate cilias, extending all round the wings. In some species, however, Mr. Haliday describes the fore-wings as transformed into broadish elytra, ciliated only behind, and with longitudinal and transverse nerves. In some species the wings are wanting, at least in the males ; the ab¬ domen is terminated either by a long attenuated joint or by a 4-valved borer in the female ; the legs are short, the anterior pair having the fe¬ mora sometimes much incrassated, with a tooth near the inner extremity (Jig. 57- 8.) ; the tibiae are simple, the tarsi 2-jointed, terminated by a vesicle f without ungues ; the base of the anterior tarsi is, in some species, armed with a tooth, at least in the males ; the middle (Jig. 57- 9.) and posterior pair of legs (Jig. 57- 10.) are simple. My figures, 57- 1 — 12., are taken from the largest species of the order which I have seen, and of which I captured a considerable number, creeping under and upon the bark of felled trees, at Sevres, in July, 1837. It appears to be nearly allied to Phlaeothrips coriacea Hal.
The eggs of Phlaeothrips statices Hal. “ are shaped like those of Culex, being cylindric, rounded at one end, and crowned with a knob at the other.” The larva (Jig. 57. 16., from De Geer) is equally active with the imago inhabiting the same situations, and differing in smaller size, softer body, distinct thoracic segments ; “ the mouth is almost alike, the antennae and legs shorter ; there are no simple eyes, and the com-
* If regarded as Mandibulata (although they are certainly not Dacnostomatous), they will possess the greatest affinity with those Biomorphotic insects which have equal sized unfolded wings, and which will be found amongst the earlier families of Neuroptera, especially the Termitidae.
f De Geer observes, that, when the animal presses this vesicle on the surface upon which it walks, its diameter is increased, and it sometimes appears concave, the con¬ cavity being in proportion to the px-essure, which made him suspect that it acted like a cupping-glass.
4
MODERN CLASSIFICATION OF INSECTS.
pound eyes are replaced by conglomerate eyes; the pupa (Jiff' 57. 17., from De Geer) resembles the perfect insect, but the articulation of the limbs is obscured by a film, and the wings enclosed in short fixed sheaths. The antennae are turned back on the head, and the insect, though it moves about, is much more sluggish than in the other states.” (Haliday, Ent. Mag. 15. p. 440.) The larvae are generally much paler coloured than the imago, being in some species blood red, whilst the imago is black ; in others, pale yellow.
These insects are found upon various plants, sometimes swarming in immense profusion in various kinds ot flowers, especially the large white hedge-convolvulus ; they are very agile, and often leap to a considerable distance when disturbed. They feed upon the juices of plants, and are often extremely injurious, especially in hot-houses and vine- houses ; the leaves upon which they reside being marked all over with small decayed patches. They also, especially, infest melons, cu¬ cumbers, kidney beans, &c. Various plans for their extirpation are given in the Gardener s Magazine , and in Major’s work on the insects which infest fruit trees.
One species, to which Mr. Haliday has applied the specific name of Thrips cerealium, infests the wheat, sometimes to a mischievous extent. This species was observed by Mr. Kirby, between the internal valve of the corolla and the grain, and taking its station in the furrow of the seed, in the bottom of which it seems to fix its rostrum, and by depriving it of its moisture, occasions it to shrink up, and become what the farmers call pungled. One sex of this species is apterous ; the larva is yellow and very nimble, and the pupa whitish, with black eyes, and very slow and sluggish. (Linn. Trans, vol. iii. p. 247.)
According to Vassalli Eandi (quoted by Mr. Haliday), this species also gnaws the stems above the knots, and causes the abortion of the ear. In the year 1805, one third of the wheat crop in Piedmont is said to have been destroyed by this minute insect ; and in the same year the wheat crops in England suffered materially from a similar cause.
Another species is very injurious to the olive tree in the territory of Pietro Santa in Tuscany, fixing itself on the under side of the leaves. As early as the month of April, four or five eggs are de¬ posited on each bud; and, as the generations of the insect succeed from spring to the end of autumn, the number of insects becomes inconceivable. (Passerini, “ Alcune notizie sopra una specie d’lnsetto
THYSANOPTERA. — TIIRIPID/E.
5
dannoso agli Olivi,” &c. in Atti dell ’ Accad. de Gcorgqfili , t. xii. and Guerin, Bullet. Zool. p. 12.)
In Hill’s Decade of Curious Insects , 1773, an insect is described under the name of Alucita pallida (the straw-coloured Chinch), which is evidently a species of Thrips, of which great numbers are asserted to have been discharged by “a studious gentleman, very subject to the headach,” whilst sneezing.
The relations of this order are very difficult : the nature of the metamorphoses would unite it with the Orthoptera or Hemiptera, whilst the structure of the wings and mouth remove it from both those orders ; the mouth, indeed, seems to be of a character almost intermediate between the Mandibulata And the Haustellata ; the setiform mandibles are very like those of the Hemiptera, whilst the general disposition of the other parts of the mouth are more like those of a real mandibulated insect. It appears doubtful to me, how¬ ever, whether the action, even of the maxillae, can be transverse, or whether the insect can be said to bite its food.
The order comprises but a single family, Thripid^e Leach , the species of which are far more numerous than has been generally sup¬ posed, as may be learned from Mr. Haliday’s valuable memoir, pub¬ lished in the Entomological Magazine > No. 15. I have also seen some plates containing magnified figures of various species of the family by M. Heeger ; but I am not aware whether they are yet published.
Order NEUROPTERA Linnaeus.
Char. Wings four, generally large, equal sized, membranaceous, with numerous areolets, posterior pair ordinarily not folded.
Mouth with transversely moveable jaws.
Abdomen of the females unarmed with a pungent multivalve ovi¬ positor.
“ Scapulae and parapleurae parallel and oblique.” Kirby.
Pupa various, in some quiescent, with the limbs folded over the breast ; in others active, and more or less resembling the perfect insect ; larva with six articulated legs.
The insects of this order, established by Linnaeus, differ from those of the preceding orders in the membranaceous structure of their four naked wings, which, together with the masticatory trophi, will suffi¬ ciently separate them from the whole of the ha.ustellated division.
b 3
6
MODERN CLASSIFICATION OF INSECTS.
From the equally mandibulated Hymenoptera, they are removed by the equal size of their wings, by their non-possession of a pungent sting, or multivalve ovipositor, and by their maxillae and labium not uniting to form a tubular apparatus. From the Trichoptera, which are still associated with them by the continental entomologists, they are separ¬ ated by the collar-like neck, pilose, branching-nerved wings, elongated coxae, and obsolete trophi, which characterise the latter named order.
This order comprises several well-known families of insects, namely, the beautiful dragon flies, the May flies, lace-winged flies, white ants, and ant-lion flies ; and derives its name from the Greek, vevpov , a nerve, and Trrepov, a wing ; in allusion to the beautiful net-work with which their wings are ornamented, forming a very numerous series of cells or areolets, far exceeding in number the cells in the wings of any other insect. The order is one of comparatively small extent, being far inferior in point of number of species to many of the other orders; but the characters, which distinguish even the few families of which it is composed, are far more discordant than those of any of the rest, there being scarcely a leading characteristic of the order which does not meet with an exception ; thus, in some genera, the posterior wings are either larger or smaller than the anterior, sometimes, as in certain genera, as Cloeon, they entirely disappear ; in others, as the female Boreus, and one of the species of Atropos, the wings are entirely ob¬ solete ; again, in the male Boreus, they are not membranaceous but leathery. The structure of the mouth is very varied ; in Libellula it assumes an anomalous appearance; and in Ephemera the jaws are en¬ tirely obsolete. The transformations are also equally varied ; indeed, Mr. MacLeay states that the essential character of the order is varied, the larvae undergoing either an incomplete (Corydalina), obtect (Mj'rmeleonina), subsemicomplete (Libellulina), or semicomplete me¬ tamorphosis (Termitina). Myrmeleon, however, most certainly has an incomplete pupa ; whilst the transformations of the Libellulidae and Ephemeridae, which (according to Latreille, as quoted by MacLeay), compose the stirps Libellulina, although peculiar and very unlike’each other, appear to me to enter into the semicomplete species of trans¬ formation. It is to be regretted that Mr. MacLeay has given no defi¬ nition of the term subsemicomplete, which he proposed for this stirps. As to the transformations of the Panorpidae, it will be seen, from my account of that family, that the theories which Mr. MacLeay enter¬ tained respecting it (Ilorce Ent. p. 433.) are completely fallacious.
NEUROPTERA.
7
The body is generally long and slender, of a soft, or but slightly scaly consistence ; the head is not generally immersed in the prothoracic cavity, the prothorax being mostly collar-shaped, and forming with the other thoracic segments a portion of the body, well distinguished from the abdomen, which is, however, ordinarily sessile ; the ocelli, two or three in number, are generally present.
There is also a great dissimilarity in the habits and economy of these insects, although the majority are predaceous. In their larva state their abodes are very diversified, some larvae residing in the water, others in damp earth, others living exposed upon plants, others again concealing themselves under a cloak of excrement, or in a pitfull of fine sand, whilst a few reside in colonies of immense extent. These insects are of an intermediate size, none exceeding our largest dragon flies in size, and none equalling in minuteness the minims of the Hymenoptera or Coleoptera.
Various insects of this order have afforded to Carus, Bowerbank, Tyrrell, and others, materials for the discovery and observation of the circulation of the blood in insects.
Linnaeus, whose character of the order was simply “ Aim 4, nudae, venis reticulatae : cauda saepius aliquo sexus adminiculo instructa, in- ermis” (Syst. Nat. t. ii. p. 901.), introduced into it the following genera, Libellula, Ephemera, Phryganea (or the caddice flies), Heme- robius, Myrmeleon, Panorpa, and Raphidia ; the winged individuals of the genus Termes being introduced into the genus Hemerobius, whilst the apterous individuals were placed amongst the apterous insects. Fabricius remedied this error by taking in Termes amongst the other Neuroptera; which name, however, he altered to Synistata, but added thereto the spring-tailed insects (Thysanura Latr .). He also raised the genus Libellula into a distinct order (or class), Odonata.
Latreille adopted the order as left by Linnaeus, with the addition of Termes; but Mr. Kirby separated Phryganea from the Neuroptera, and formed it into a distinct order under the name Trichoptera, in which he has been followed by English entomologists. MacLeay, how¬ ever, further united the Perlidae with the Trichoptera, in consequence of having evidently misunderstood Latreille’s sections given in the Genera Crust, et Ins. t. iii. p. 209. and 212.*, and dividing Latreille’s
* Mr. MacLeay says that the Pcrlariae of Latreille’s Gen. Crust., &c., or the Phryganeidae of Lamarck, is evidently a natural group, whose larvae (admirably de¬ scribed by Aristotle under the name of Xylopthori) are aquatic, and live in tubes or sheaths made by themselves; and he then insists that the larvae, metamorphoses,
B 4
8
MODERN CLASSIFICATION OF INSECTS'.
little group Megalopteres into two, keeping Corydalis (Corydalina MacLeay ) in the order Neuroptera, and giving Megaloptera Latreille , as a distinct and osculant group between that order and the Trichop- tera : Boreus being also removed from the Neuroptera, and forming a distinct osculant group between it and the Orthoptera. It is scarcely possible to conceive a more unnatural mode of treating this order. More recently M. Brulle, in his Entomology of the Morea, has en¬ deavoured to construct another distribution of these insects, which he divides into four orders, namely : —
1st, The Dictyoptera*, comprising Libellula, Ephemera, and Perla.
2nd, The Isoptera, consisting of the single genus Termes.
3rd, The Trichoptera, consisting of the single genus Phryganea.
4th, The Neuroptera, containing the remainder of the Linnaean genera. The genera Raphidia, Mantispa, and Psocus being removed to the order Orthoptera.
In rejecting these views, both of Brulle and MacLeay, I am influ¬ enced by the evident diversity which exists amongst these insects, whereby groups, most nearly related to each other, would be removed far apart were we to adopt them ; thus ex. gr. Perla is clearly more nearly related to some of the genera left by Brulle in his restricted order Neuroptera than it is to Ephemera. It is for the same reason that I am not fully convinced of the propriety of keeping Phryganea as a distinct order, although I have thought it better to follow the steps of Kirby, Stephens, and MacLeay, respecting its separation, rather than unite it with the rest of the Neuroptera into one order as Latreille and Pictet have done.
Regarding then the Neuroptera as an order distinct from the Tri¬ choptera, which is to be restricted to Phryganea, we find it related of course, on the one Rand, to the Trichoptera, whilst, on the other, it closely approximates to the Orthoptera. The curious genus Mantispa,
antennas, mouths, and wings of Perla and Phryganea, all manifest their close affinity, ( Horce, Ent. p. 430.) Now Latreille has nowhere given Phryganea as portion of the Perlariae, as Mr. MacLeay clearly thought he had done ; for had he studied the tabular distribution given in a preceding page of the “ Genera,” he would have seen that Lati’eille had not the slightest idea of uniting the Perlida? and Phryganeidae into one group ; whilst, had he known the larva and metamorphoses of Perla, he would have found that they were as unlike those of Phryganea, as are the mouths and wings of the two genera.
* Leach had previously used this name for the genus Blatta; its application, there¬ fore, to other insects was not warranted.
NEUROPTERA,
9
alternately placed by Latreille amongst the Orthoptera and Neurop- tera, has been supposed by MacLeay to constitute a passage between the two orders ; but from what I have already advanced concerning it (Vol. I. p. 412. note f), I am but little inclined to adopt this relation beyond one of analogy ; if, indeed, the pupa of Mantispa were ascer¬ tained to be active and semicomplete, there might be better grounds for this relation. In like manner Mr. MacLeay has considered the Panorpideous genus Boreus as a connecting link between the two orders ; influenced, indeed, not by the real characters of the insect, but apparently by Panzer having called it a Gryllus, and by the in¬ sufficient observation of early authors. There exist, however, nearer points of relation between the two orders than those pointed out by MacLeay; thus the genus Termes, in the structure of the mouth, and especially thegaleated maxillae and labium, is almost identical with the Orthoptera. The same may also be said of the Perlidae, which have also the posterior wings longitudinally folded, and the extremity of the body terminated by articulated filaments ; their pupa state is also active, and the larva resembles the imago.
Various plans have been suggested for the classification of this order. Latreille, in his various works, has adopted an arrangement founded upon the natural habits of these insects, commencing with those “ vi- vant de rapine,” at the head of which the Libellulae are pre-eminent, followed by Ephemera, which, although destitute of organs of nutrition in the perfect state, is predaceous whilst a larva, and is closely allied to Agrion in the antennae, form of head, size of eyes, &c. These are followed by other predaceous tribes, which are succeeded by the omnivorous white ants, and this series is closely followed by the Phry- ganeae. The peculiarities of these insects in the preparatory states “ consolident l’etablissement et la suite des families qui remplissent cet ordre.” (Latr. Cons. Gen. p. 73.) In the Regne Animal (vol. v. p. 234.) we, however, find a more precise sketch of this proposed ar¬ rangement : —
1. Insectes carnassiers, demi-metamorphose, larves aquatiques.
2. Insectes carnassiers, metamorphose complete, larves terrestres ou aquatiques.
3. Insectes carnassiers, ou omnivores, terrestres, demi-metamorphose.
[4. Insectes herbivores, metamorphose complete, larves aquatiques,
se construisant des domiciles portatifs. Phryganea.]
In the genera Crustaceorum, the arrangement of the families of
10
MODERN CLASSIFICATION OF INSECTS.
which the order is composed, founded upon these considerations, was as follows : —
Tribe 1. Subulicornes (having very short subulate antennae), com¬ posed of (a) the mandibulated Libellulae ; and (b) the emandibulated Ephemerae.
Tribe 2. Filicornes (having long, multi-articulate antennae), com¬ posed of (a) the following mandibulated types, Panorpa, Myrmeleon, Hcmerobius, Sialis, Corydalis (all with 5-jointed tarsi), Termes and Raphidia (with 4-jointed tarsi), Psocus (with 2 or 3 -jointed tarsi), and Perla (with 3-jointed tarsi), and of (b) the single emandibulated genus Phryganea.
In the Regne Animal the same arrangement of the families is pre¬ served ; but they are divided into three primary tribes : — 1. Subu¬ licornes (as above) ; 2. Planipennes ; and, 3. Plicipennes, the second of which comprises all the mandibulated filicorn species ; and the Pli¬ cipennes, the emandibulated Phryganea ; the Planipennes being com¬ posed of the five following, families, Panorpates, Myrmeleonides, Hemerobines, Termitines, and Perlides.
To this arrangement M. Pictet and Mr. Newman (who have both particularly studied this order of insects) object, on the ground that the section Planipennes is of too heterogeneous a nature ; and the former author ( Mem, Sialis) accordingly proposes the adoption of six families in the order (including the Phryganea), namely : 1. Subu¬ licornes Latr. ; 2. Planipennes (Hemerobius and Myrmeleon); 3. Pa¬ norpates ; 4. Termitines ; 5. Perlides ; 6. Phryganides. If we thus, how¬ ever, separate the Latreillian Planipennes into four groups, it appears to me to be equally necessary to raise the two divisions of the Subu¬ licornes to a like rank, which indeed Mr. Newman has done ( Ent . Mag. No. 18. p.237.) ; but it does not appear to me that a sufficient equality has been maintained in the construction of the natural families.
Taking the transformations as the ground of the distribution of the order, it appears to me to form two primary divisions : —
1. Those with an active pupa, undergoing a metamorphosis which, for want of a better name, we may, with MacLeay, term subsemicomplete; in all which there is a greater dissimilarity between the larva and imago states than exists in the insects typical of the monomorphous, semicomplete metamorphosis (Gryllus, &c.) Here belong the Psocidoe and Termitidae, which have terrestrial larvae, and the Libellulidae
NEUROPTERA.
11
Ephemeridae, and Perlidae, which are aquatic in their preparatory states. I term the species of this division Biomorphotic insects.
2. Those which have quiescent incomplete pupae, which, however, acquire the power of locomotion shortly before the assumption of the perfect state. This division (Subnecromorphotica) comprises the families Myrmeleonidae, Hemerobiidae, Sialidse, Panorpidae, Raphidiidae and Mantispidae.* Other arrangements might be adopted by considering other characters as of primary importance. The succession of the fami¬ lies proposed by Pictet appears the most natural of any hitherto pub¬ lished. The families, 1. Termitidae ; 2. Psocidae ; and, 3. Perlidae, have the greatest relation to the Orthoptera ; to these succeed the 4th family Ephemeridae, and the 5th Libellulidae ; the 6th family Myrmeleonidae, in the general form of the body and wings, appears to be the nearest to the Libellulidae ; to these succeed, 7th, the Hemerobiidae ; 8th, the Sialidae ; 9th, the Panorpidae ; 10th, the Raphidiidae; and, 11th, the Mantispidae, which last also manifest a near relation to the Or¬ thoptera.
The family TERMiTiD^t is composed of the various species of exotic insects, known under the name of white ants, placed by Lin¬ naeus in the order Aptera, on account of the apterous condition of
* This arrangement nearly corresponds with that suggested by Latreille in his Hist . Nat. Gen. Ins. tom. xiii. p. 100., as more natural than that adopted in the body of his work.
f Bibliogr. Refer, to the Termitidae.
Fabricius, J. C. Niihere bestimmung des Geschlechts des weissen Ameisen, in Besch. der Berl. Ges. Natur. fr. b. i. 1775.
Koenig. Naturg. weis. Ameis. in ditto, b. iv. 1775.
Smeathman. Some Account of the Termites in Phil. Trans, vol. Ixxi. 1781. — Ditto. Separate. Lond. 1781. 8vo. — Ditto. Transl. by Rigaud. Paris, 1786. Swartz, in Vetensk. Acad, nya Ilandl. 1792.
Sparrinan. Voy. to the Cape of Good Hope, 2 vols. Lond. 4to. 1785.
Latreille. Decouverte de Nids de Termes, in Mag. Encycl. 1797, and Bull. Soc.
Phil. t. i. 1798. — Ditto, Hist. Nat. Insectes, vol. xiii.
Kalm, in Scheved. Acad. Abhandl. 16. st. and Fuessl. N. Ent. Mag. 3 band.
Besch. der Berl. Nat. Gesellsch. 1 band (on the Queen of the White Ants).
Kollar. Brasiliens Vorzuglich lastige Insecten. Wien. 1832. — Ditto, in Isis of Oken, 1833. (T. flavipes).
De Geer. Memoires, vols. iii. and vii.
Pertg. Delect. An. art. Brasilia?.
12
MODERN CLASSIFICATION OF INSECTS.
some of the individuals, whilst he regarded the winged ones as be¬ longing to the neuropterous genus Hemerobius.
M. Brulle proposes to form these insects into a distinct order in his work on the insects of the Morea, named Isoptera ; whilst Mr. Kirby regards them as forming, together with the ants, to which they are allied in so many points in their economy, a passage between the orders Neuroptera and Hymenoptera.
These insects live in communities of countless numbers, of which the majority are apterous. The males and females are, however, winged, and are distinguished from the other Neuroptera by the following characters. The body is oblong, depressed, and of nearly equal breadth throughout {Jig. 58. 1. represents a large Brazilian
Fig . 58.
species) ; the head is of moderate size, horizontal, and rounded behind {Jig- 58.2. front of head) ; the eyes lateral, prominent, and subglobose; the ocelli, two in number, more or less distinct, placed between the eyes, the third ocellus being subobsolete ; the antennae short, with about twenty submoniliform joints, the basal joint being the largest {fig. 58. 9.) ; the clypeus and labrum are distinct {Jig. 58. 2.), the latter produced over the mandibles, and subtriangular in form, with the sides rounded. The mandibles {fig. 58. 3.) are horny, flattened, and triangular in form, with several teeth on the inner edge ; the maxillae {fig. 58. 4. under, 58. 5. upper side of the maxillae) are flat, horny, and terminated by two strong hooked teeth, and defended by a very broad external lobe or galea {fig. 58. 4. 5. x .) ; the maxillary palpi are rather longer than the maxillae, filiform, and 5-jointed ; the labium {fig. 58. 6. beneath, 7. laterally) is very perfect in its formation, being of large size, and occupying the greater portion of the under surface of the head ; the mentum is coriaceous, transverse, with the fore mar-
NEUROPTERA. — TERMITID/E. 13
gin rounded ; the labium itself is divided at the apex into four nearly equal conical lobes ; and the labial palpi are filiform and 3-jointed. Within the mouth, attached to the inner base of the labrum, arises a large coriaceous lobe ( fig . 58. 7. 0. and 58. 8. detached), somewhat emarginate in front, and which is the lingua, here as fully developed as in the saltatorial Orthoptera and Libellulidm.
The three thoracic segments are distinct ; the prothorax of mo- deratesize, shield-like, and either transversely quadrate or semicircular, with the anterior margin straight, and the posterior rounded ; the meso- and meta-thorax are of nearly equal size ; the wings are nearly twice as long as the body, narrow, and of equal size, they are not so hyaline as in the majority of the insects of this order; the costal and subcostal nerves are very robust, but all the other nerves are but slightly visible ; when at rest they are carried flat upon the back ; the legs are rather short, slender, and simple ; the tibiae are cylindrical, with two or three spurs; the tarsi (fig. 58. 10.) are 4-jointed, the three basal joints being very short and hairy beneath ; the abdomen is flattened, with transverse segments, and terminated at the sides by two minute conical 2-jointed styles (fig. 58. n. The figures 58. l — n. are taken from the large Brazilian species figured.)
With the exception of two or three small species of this family (T. l.ucifugus Rossi , T. flavicollis Fab., and T. flavipes Kollar in Isis, 1833), these insects are chiefly confined to the tropics, where the immense numbers of which their communities consist, together with their devas¬ tating powers, render them the most absolute pests of mankind. They attack furniture, wood-work, and merchandise of every kind ; and their instinctive powers are so great, that every particle of furniture in a house may be destroyed without their presence being even suspected, as they form their burrows under ground, and make their places of exit immediately beneath the legs of tables, &c., of which they com¬ pletely eat away the interior, leaving only a thin outer shell, which crumbles to dust on being moved. The nests of these insects are of a very large size, and varied in form according to the species. That of T. fatale Linn. (Bellicosus Smeathm .) is sometimes not less than ten or twelve feet high, of a conical form, with numerous conical turrets on its sides ; it is formed of clay, and, being soon coated with grass, looks like a haycock. The strength of these nests is so great that, when raised to little more than half their height, it is tile practice for the wild bulls to mount upon them as sentinels, whilst the rest of the
14
MODERN CLASSIFICATION OF INSECTS.
herd is feeding; and Smeathman and four of his companions mounted on the top of one of them to obtain a view of any vessel which might come in sight. The nests of T. atrox and mordax are cylindrical pillars, three quarters of a yard high, with a projecting roof; whilst T. destructor Fab?' . (T. arborum Smeat/im.) constructs its nests of different sizes, amongst the branches of trees, seventy or eighty feet high. T. viarum appears, from the observations of Smeathman, to re¬ side in holes in the ground. T. lucifugus makes its lodgements in the trunks of pines and oaks, in which they form a number of irregular burrows. Dr. Burmeister showed me a colony of T. flavipes at Berlin, which he kept in a flat earthenware jar filled with rotten debris, and covered with damp pieces of wood, in which the insects burrowed.
The societies of these insects consist, according to Latreille (who in¬ vestigated the economy of T. lucifugus, which he discovered at Bor¬ deaux), of five kinds of individuals, namely : 1. Males , and, 2. Fe¬ males , closely resembling each other externally, and agreeing with the characters given above ; 3. Individuals, described by Smeathman and Fabricius as pupae, but called neuters by Latreille and Kirby, and soldiers by Smeathman (fig* 58. 14. T. flavipes), having a soft, elon¬ gate, oval body, destitute of wings, and a head of gigantic size, armed with long and powerful sickle-shaped jaws, in which the under, as well as the upper, side of the head is horny, with the maxillae and labrum very minute, and the palpi long and slender. My Jig. 58. 15. repre¬ sents the under side of the head of T. flavipes in which the upper lip is long and entire ; but in another species, from Fernando Po, in my collection, it is very deeply notched (^.58.16.); the eyes appear entirely wanting ; the parts of the mouth of these members have not been previously described. These individuals are much less nume¬ rous than the workers, being in the proportion of 1 to 100. They are employed as sentinels and soldiers, making their appearance when the nest is invaded, attacking the intruders, and inciting the labourers to work. 4. Apterous individuals, called larvae by Latreille, Kirby, &c., and workers by Smeathman, very much resembling the winged individuals, but with the head larger and rounded ; the eyes and ocelli wanting; the mandibles not larger than in the winged individuals ; the thorax, with the three segments, distinct and wingless (Jig. 58. 12. T. flavipes); these are considerably smaller than the so-called neuters, and are the most numerous and most active portion of the community; they are the workers and architects of the nest ; they collect food,
NEUROPTERA. - TERMITIDjE.
15
form covered ways, guard the males and females, and take care of the eggs and young : and, 5. Pupae, first observed by Latreille, and de¬ scribed by him as resembling the workers, but having four white tu¬ bercles on the back of the meso- and meta-thorax, in the shape of rudimental wings. In a small African species from Fernando Po, of which the nest is in the museum of the Rev. F. W. Hope, the pupae {fig* 58. 13.) are furnished with 4-wing tubercles extending beyond the body, with large lateral eyes. These individuals bear a great re¬ semblance to some of the perfect Cercopidae ; no other figures have hitherto been given of these insects in this state. Latreille found these pupae in the nests of T. lucifugus in the spring ; and in the month of June following, the winged individuals make their ap¬ pearance in prodigious numbers, swarming during the evening and night ; the latter shortly afterwards pair, and after impregnation, the females (as in the ants, with which these insects possess a very great analogy), lose their wings, which easily fall off* ; they are then made prisoners by the workers, in order to become the founders of fresh colonies, and conducted into the interior of the nest, where the body of the female becomes swollen to an enormous size, exceeding by 20,000 or 30,000 times the bulk of one of the workers, when she com¬ mences laying her eggs ; the amazing number of 80,000 being dis¬ charged in the course of twenty-four hours. From these circumstances, Latreille {Hist. Ncit. Ins. vol. xiii. p. 65.) was led to believe that the fourth kind of individuals, or the workers of Smeathman, are larvae ; that the fifth kind are pupae ; that the soldiers are a peculiar order which never acquire wings, and are not capable of reproduction, being thus analogous to the neuters of the bees and ants ; and that those specimens which are met with, without wings, in the nest, after the period of pairing, are females which have pulled off their wings, and have survived the process of oviposition.
The nature of these various kinds of individuals, however, requires a more minute investigation than it has yet received. Burmeister well observes, that there is no other instance in the whole animal world in which the undeveloped young labour for the old ; and is thence in¬ duced to doubt that the workers are really larvae, to which may be added the circumstance that these so-called larvae still retain their
* The account given by Mr. Davis of insects, like Nemourse, lighting in swarms upon a ship at anchor off Bahia in Brazil, and biting off their wings, appears to re¬ late to a small species of Termes. ( Ent . Mag . No. 24.)
16
MODERN CLASSIFICATION OF INSECTS.
form when the winged individuals appear. Kirby indeed suggests, that as these insects belong to an order whose metamorphosis is semi- complete, the office of working for the society may devolve upon the larvae ( Introd . vol. ii. p. 30.) ; and Latreille endeavours to account for the circumstance that, at the time of the winged individuals coupling, a great number of specimens remain in the nest under the form ot larvae, by supposing that these ‘ ne doivent subir leur derniere meta¬ morphose que l’annee suivante ; ” making them to be two years in ar¬ riving at perfection, which is, however, but a mere supposition. As to the large headed individuals, their right to the name of neuters has been doubted by Huber. ( Nouv . Ohs. vol. ii. p. 444. note *.)■ Kirby says that in all respects they bear a stronger analogy to the larvae than to the perfect insects, and after all may possibly turn out to be larvae, perhaps of the males ( Introd . vol. ii. p. 34. note *) ; and Burmeister observes that he does not see why these neuters should be merely de¬ fenders, as the neuters amongst all other social insects are the true workers ( Manual of Ent. Transl. p. 533.). As to the individuals which have lost their wings, Burmeister, who dissected one of them, did not find the least trace of external or internal genitalia, and is thence induced to believe that they are real neuters. I cannot, how¬ ever, adopt this opinion, nor the hypothesis which he has founded thereon, as I am inclined to think that his investigation of the internal anatomy of the individual was not sufficiently precise, and that this specimen was a male or female which had lost its wings in the usual way. Moreover, his hypothesis does not account for the exist¬ ence of the large headed individuals. On the other hand, I would even venture to suggest, from a knowledge of the modifications to which some individuals of the Orth opt era, Hemiptera, and Hymen- optera are subject, that these large headed individuals, as well as the so-called larvae, remain permanently apterous, without altering their form *, being like the wingless specimens of Velia currens retarded in their transformations, their development stopping short before their arrival at maturity, and thereby some individuals gaining an enlarged head in order to compensate for their ultimate want of wings ; and that the real larvae of the comparatively few specimens, which ultimately become winged, are as yet unknown.j-
* The want of rudimental wing-cases and the structure of the head and mouth of the soldiers seem to me to prove this completely, at least as regards these indivi¬ duals.
f The larvae and neuters of Termes Viarum are described by Smeathman as pos¬ sessing eyes.
NEUIIOPTERA. - PSOCID/E.
17
The reader who would learn more ample particulars relative to the natural history of these insects, their various duties, the internal economy of the nest, and their wonderful instincts, must consult Smeathman’s Memoir above referred to, Kirby and Spence’s Intro¬ duction. , vols. i. and ii., and Latreille’s Hist. Nat. vol. iii., as well as my article Termitidse in the Brit. Cyclop, of Nat. Hist. The spe¬ cies of this family are evidently more numerous than has been sup¬ posed, but they require a more rigorous investigation than has hitherto been given to them. Some exotic species (fig. 60. 16.), having 3-jointed tarsi, wings not longer than the body, and the anterior legs dilated (60. 18. 17. maxilla), compose the genus Embia Latr. They seem more nearly related to the Perlidae. They form the subject of my mono¬ graph, published in the Linncean Trans, vol. xvii.
The family Psocid^: * Leacli. comprises a rather numerous series of minute insects, at once distinguished by the almost obsolete la¬ bial palpi ; the 2 or 3-jointed tarsi ; the smaller size of the posterior wings, which are not folded, and by the slenderness of the antennae, which are long and setaceous, composed of about thirteen joints ; the first of which is the largest, the third the longest, and the remainder gradually diminishing in length ; the upper lip is large ; the man¬ dibles (fig. 59. 2. 3.) horny, trigonate, with a tooth near the tip in¬ side, and another (much stronger in one jaw than the other), near the base inside ; the maxillae (fig. 59. 4.) are elongated, fleshy at the tip, and armed with a long, slender, curved, horny process, aris¬ ing from the base, and longer than the maxillae ; the maxillary palpi are 4-jointed; the labial apparatus (fig. 59. 5.) is large ; the mentum is a large leathery plate, reaching to the base of the head beneath ; the labium subquadrate, with a deep, longitudinal, central impression ; the sides are rather rounded, and the middle, in front, produced into
* Bibliogr. Refer, to the Psocid.e.
Latreille, in Bull. Soc. Philomat. an. 3. Nos. 41 . and 42. — Ditto, in Coquebert. Illustr. Iconogr. Ins. tab. 2.
Phil. Trans. 1693, Allen; 1701, Derham ; 1724, Stackhouse. ( Atropos pulsatorium. ) A ritzsch., in Germar, Mag. Ent. vol. iv. (Anatomy Atropos pulsator.)
Carpenter, in Mag. Nat. Hist. No. 10.
Stephens , Curtis, Fahricius.
VOL. II.
C
18 MODERN CLASSIFICATION OF INSECTS.
Fig. 59.
two lobes, at the side of which two small rounded lobes are attached; the labial palpi have been described by Latreille and Curtis as wanting, but they appear to me to be represented by the last-mentioned pair of lobes ; the eyes are of moderate size, semiglobose, lateral, and prominent ; the ocelli are three in number, and placed in a triangle between the eyes {fig. 59. 6.) ; the body is short, gibbose, ovate, and soft ; the prothorax is very short ; the meso- and meta-thorax larger and deeply impressed ; the wings are hyaline, deflexed, with con¬ spicuous veins; the anterior larger than the posterior, with a large stigma, and a few irregular, longitudinal, and transverse nerves ; they are often variegated and coloured ; the lower wings are not folded ; and the veins are differently arranged to those of the anterior pair; the abdomen is short, ovate, and convex, the ovipositor, which exists in the females, enclosed in two valves, not being exserted ; the legs are long and slender ; the tarsi c2 or 3-jointed.
These minute insects frequent the trunks of trees, palings, old walls, stones covered with lichens, old books, &c., for the purpose of feeding, either upon the still more minute animalculae, which inhabit those situations, or, more probably, upon the decaying vegetable matter to be there met with. They are extremely active, and when ap¬ proached they endeavour to hide themselves' by running to the op¬ posite side of the trunk of the tree, or other object on which they are stationed. The perfect insects are produced towards the end of the summer, when they sometimes appear in great numbers. The larvae and pupae are equally active with the imago, from which the former differ in being apterous, whilst the pupae have rudimental wings.
Latreille published a monograph of these insects in Coqueberit’s
NEUROPTERA.
PSOCIDiE.
19
Iconography ; and more recently Curtis, and especially Stephens, have described many additional species, proposing various divisions founded upon the variation of the nerves of the wings. It appears to me, however, that a more minute structural investigation of these in¬ sects is required, as I am inclined to think they vary materially in th e sexes. In the month of July, I have observed on the trunks of apple trees a species which I believe to be P. 4-maculatus Latr.; the smaller specimens, having the wings veined as in Jig. 59. 8., and the tarsi, distinctly 3-jointed (Jig. 59. 9.), were produced from pupse (fig- 59. to), which had four long wing covers, 2-jointed tarsi, (fig. 59. 12.), and 13-jointed antennas (fig. 59. 11.) ; the females, as I pre¬ sume them to be of the same species (fig. 59. l.), were larger, with the veins differently arranged, and with 2-jointed tarsi (fig. 59. 7.). I found in company with these insects a number of specimens in the state represented in Jig. 59. 13., and which, from their large size and the markings of the head, destitute of ocelli, I presume are the pupae of the females, although the small size of the rudimental wing-cases, and of the meso- and meta-thorax (fig. 59. 14. thoracic segments la¬ terally), together with the 3 jointed tarsi (fig. 59. 15.), might lead to the opinion that these individuals will never acquire wings ; the struc¬ ture of their mouths also agrees with that of the females. If my sup¬ position, as to the specific identity of all these individuals, be correct, the genus Ccecilius of Curtis must be rejected, being founded upon a sexual character.
M. V. Audouin has communicated to me an observation made by him, in which a female winged Psocus was seen to weave a web over its eggs, which it had deposited in the impressed parts of leaves formed by the veins of the leaf. Likewise that, in another species, the eggs, eight in number, were arranged on a leaf in an irregular circle, with the tips all pointing to the centre of the circle. In the month of August, I have found amongst old papers specimens of a minute species in the state agreeing with Jig. 59. 13., having four minute rudimental wing-cases, but with 2-jointed tarsi. These insects I presume to be fully developed females of the insufficientlyAharac- terised Atropos fatidicum ; with them I found many specimens still smaller, with a more slender body, and with only two rather short rudimental wing-cases (Jig. 59. 18.), as well as a single specimen (fig. 59. 16.) agreeing with the latter, except that the two wings were larger ; the nerves more distinct ; the tarsi only 2-jointed (Jig. 59. 17.) ;
c 2
20
MODERN CLASSIFICATION OF INSECTS.
tli is I presume to be the male, and the preceding the male pupa of the same insect, which, from a consideration of its characters, I have separated as a distinct genus, named after Lachesis, one of the Fates.
The Atropos pulsatorius (Jiff. 59. 19.) is a minute, almost colourless insect, found in great numbers in ill-preserved collections of insects, plants, old books, &c., to which it is very injurious, by eating all the more minute portions ; the different shape of the head, and proportion of the thoracic segments destitute of wings, united with its 3-jointed tarsi (Jig. 59. 21.), and thickened hind legs, well distinguishes it from Psocus. Latreille, however, throws out a hint that it may be the larva of Psocus abdominalis Fab. (pedicularius Lcitr* Hist. Nat. his. vol. xiii. p. 71. and 73.), which scarcely appears to me to be possible ; although, from what I have noticed above, as to the variations oc¬ curring in Psocus, it is impossible to assert that such is not the case. I have noticed that they are killed in a very short time, when shut up in a box with camphor. This species is commonly called the death- watch, from its habit of making a slight tapping noise like the ticking of a watch, somewhat similar to that made by the species of Anobium. There are several papers in the early volumes of the Philosophical Transactions , above referred to, upon this subject.
The genus Coniopteryx, placed by Curtis and Stephens in this family, evidently belongs to the Hemerobiidae.
The family Perlid^ % Leach , is of small extent, comprising but few species of moderate size (Jig. 60. \. P. marginata), distinguished by the large size of the posterior pair of wings, which are folded, the 3-jointed tarsi, the existence of labial palpi, and the ordinarily rudi- mental state of the mandibles, and membrano-coriaceous structure of
* Bieliogr. Refer, to the Perlih^e.
Pictet. Mem. sur les Larves des Nemoures, Ann. Sc. Nat. August, 1832. — Ditto, on Perla, in ditto, January, 1833. — Ditto, in Mem. Soc. Physiq. et d’Hisfc. Nat. Geneve, vol. vii. (new Nemours. )
Newman, in Entomological Magazine, vol. i. p. 415. (Isogenus.) Vol. iii. p. 500. (Chloroperla). Vol. v. p. 175. (Pteronarcys and other North American species). Vol. vi. p. 401 . Likewise a monograph of the caudated species about to be published.
Suckow, in Zeitschr. Organische Phys. t. ii. No. 3. March, 1828.
Lucas, in Ann. Sc. Nat. December, 1832, t. xxvii.
i. si
Westwood, in Griff. An. Kingd. (Eusthenia. )
Stephens, Olivier (Enc. Meth.) Curtis, Sc.
NEUROPTEIIA.
PERLIDiE.
21
Fig. 60.
the other parts of the mouth. The body is oblong, depressed, and of equal breadth throughout, the head (y?y.60.3.under side) being flat, as broad or broader than the prothorax, which is large, flat, and quadrate; the eyes prominent, semiglobose, and lateral; the ocelli three, in a tri¬ angle, between the eyes ; the antennae nearly as long as the body, and multiarticulate ; the basal joint being largest, and the third and following exceedingly short ; the upper lip is transverse, and very short ; the man¬ dibles in Perla are small, flat, and membranous ( fig. 60. 4.). In a beauti¬ ful Australian species, they are horny and toothed (Jig. 60. 15.), whence I have formed this insect into a distinct genus, Eusthenia spectabilis Westw. ( Griffith, An. Kingd .) ; in Nemoura they are also horny, and armed with several teeth ; the maxillae are widely apart, with a long basal articulation, and two short and slender terminal lobes ; the max¬ illary palpi are slender, and 5-jointed (Jig. 60. 5.) ; the mentum (Jig. 60. 6.) is large, covering the greater part of the under side of the head ; the labium is smaller and quadrate, deeply slit down the middle ; the lingua (overlooked by Curtis) being well developed, not slit, and occupying its internal face ; the labial palpi are 3-jointed ; the three thoracic segments are nearly equally developed ; the abdomen is sessile, soft, depressed, of equal breadth, 9-jointed, and in the large species furnished with two long and slender articulated filaments ; the wings are longer than the abdomen, upon which they are horizontally extended at rest, the posterior pair being the largest, and folded ; the legs are of moderate length, compressed, and simple; the tibial spurs very short ; the third or terminal joint of the tarsi is larger than the two preceding united in Perla (Jig. 60. 7.) ; but in Nemoura the joints are of equal length. There is a very great diversity in the sexes of the typical genus Perla, the males being much smaller than the fe¬ males, with very short wings (Curtis and Lucas, in Ann. Sc. Nat.,
c 3
22
MODERN CLASSIFICATION OF INSECTS.
Dec. 1 832 ; fig. 60. 2. P. cephalotes $ *) ; the latter circumstance also occurs in Nemoura trifasciata Pictet. These insects frequent damp marshy situations, and the borders of lakes and rivers, resting upon stones, palings, and plants, growing close to the water’s edge ; they are sluggish in their movements, and the larger species are well known to the angler as an excellent bait for trout ; Perla bicau- data appearing in April, being called the Stone-fly; Chlor'operla viridis in May, termed the Yellow Sally; and a species of Nemoura in Sep¬ tember, called the Willow-fly. ( Ronald's Fly fisher s Entomology.') Curtis gives the name of Willow-fly to Chloroperla viridis.
In their preparatory states, these insects reside in the water : the female, according to Scopoli ( Ent.Carn . p. 705.), Suckow, and Curtis, carries a globular bundle of little black shining eggs at the apex of the abdomen, enclosed in a valve or bag ; such is also the case with the Ephemerae. In the works of Geoffroy, Olivier, Fabricius, Latreille, &c., the transformations of these insects are described as being similar to those of the Phryganeae ; namely, having a cased larva, and an in¬ active pupa ; and Mr. MacLeay, misled by this statement, has united the Perlidse in the same order with the Phryganeae, with which, indeed, they agree in the large size of the posterior folded wings, and the weak structure of the mouth. The error originated with Reaumur, who reared a small bicaudated Perla in a vessel, in which “ M. l’Abbe Nollet avait mis ou cru n’avoir mis que nos teignes a fourreaux dont l’envelope est une espece de ruban vert roule,” or a cased larva of one of the Phryganeae. ( Memoires , tom. iii. p. 1 78. pi. 13. f. 12. and pi. 14. f. 8. 9. and 10.) It is evident, from a reference to Latreille’s Hist. Nat. vol. xiii. p. 47*, that his statements relative to the trans¬ formations of this group are derived from the memoir of Reaumur above referred to, and the history given by GeofFroy (Hist. Abregee des Ins. tom. ii. p. 230.) ; but Geoffroy himself informs us in p. 233., that the history which he gives of the genus is that of “la perle jaune,” an insect only two lines long, and which evidently does not belong to the family.
These statements, however, at least so far as the present family is concerned, are incorrect ; the larvae of the Perlidae being naked, not
* In a beautiful species from Van Dieman’s Land, which I have received from Mr. R. H. Lewis, the females are occasionally furnished with only short wings. One thus constructed, in the collection of the Rev. F.W. Hope, has a bundle of eggs still attached to the extremity of the abdomen. (Eusthenia diversipcs W. )
NEUROFTERA - PERLIDiE.
23
enclosed in a case, and in general form resembling the imago, except in wanting wings ; whilst the pupa is active, having a still greater re¬ semblance to the imago, possessing the four rudimental wing-cases. In a memoir published by Goeze in Per Naturf or seller, st. iii. so long ago as 1774, a figure of the pupa of Perla bicaudata was given, answering to this description ; and specimens of the pupae are pre¬ served in the Linnaean collection. I likewise possess several (Jig. 60. 8.), as well as the exuviae cast on the insect’s arrival at the perfect state, and which are found attached to plants, Sic., in the vicinity of the water in which the larvae and pupae have resided. Dr. Suckow has also (in a memoir written with the view to prove that the Semblis [Perla] bi¬ caudata, and Semblis [Sialis] lutaria belonged to different genera, as, indeed, they had long been considered by Latreille, and published in the Zeitsclirift fur die Organische Physik ) described the Perla bi¬ caudata in its various states. More recently Mr. Newman has given a sketch of the larva of P. bicaudata (Put. Mag. vol. i. pi. 3. f. 10); and M. Pictet has published two memoirs, detailing the history of various species of Perla and Nemoura, agreeing Avith the character given above. These larvae prefer the most rapid parts of streams : they crawl about slowly, preferring to remain stationary under stones ; they are carnivorous ; they shed their skins several times (at least, in Nemoura) ; and they generally crawl out of the water when about to assume the perfect state. M. Pictet has described these larvae in detail ; it will, however, be sufficient to notice that, unlike the imago, the mandibles in the larvae of Perla (fig. 60. 9.) are robust and toothed, as well as the maxillae (fig. 60. 10.); the eyes are prominent and la¬ teral, and in the place of ocelli I observe three black dots between the eyes, which M. Pictet has not described. The tarsi in the pupae of Perla (fig. 60. li.) appear to me to be composed of three joints, the two basal ones being very minute, the first almost hidden from view ; in the larvae of Nemoura the tarsi are 2-jointed. M. Pictet has described two singular modifications in the respiratory organs of these insects. In the larvae of the large species composing the genus Perla, as re¬ stricted in my Generic Synojosis, each of the three thoracic segments is furnished with a pair of tufts of short external filaments, each tuft being composed of three distinct pencils, each having a distinct origin (fig. 60. 12.).
In the Perla virescens Pictet (evidently a Chloroperla Newm.), and in Perla nigra Pictet (which will probably form a different subgenus,
c 4
24-
modern CLASSIFICATION OF INSECTS.
intermediate between Isogenus and Nemoura), the larvae are des¬ titute of these external organs of respiration.
In Nemoura cinerea Pictet , Oliv., the under surface of the prothorax is furnished with six elongated filamentous sacs (fig. 60. 14.), similar to the sacs observed on the abdomen of the larvae of Phryganeae. These organs do not exist in the five other species of the genus, of which M. Pictet has described the larvae, thus proving the slight importance of these modifications of the respiratory apparatus in the Annulosa. The rudiments of the wing-cases are perceived in the enlarged posterior angles of the meso and metathorax of the larva, and the pupa state is only to be known by the increased size of these wing-cases, which ase developpent peu-a-peu dans la nymphe/' In the genus Perla, as now restricted, these wing-cases are much less distinct than in the P. microcephala Piet. (which is, I apprehend, an Isogenus*), Chloroperlae (P. virescens Piet.), P. nigra, and the Nemourae ; in all which the wing-cases in the pupae are detached, and considerably elongated (fig. 60. 13.). The resemblance between the larvae of the smaller species of caudated Perlidae, and the Nemoura is so complete, that M. Pictet could not discover any “ caractere constant pour les distinguer,” although in the perfect state the latter are destitute of the pair of anal filaments which exist in their larvae. A species of this family, Semblis viridis (Chloroperla ?) has been made one of the subjects of Dr. Carus’s observations on the cir¬ culation of the blood in insects. (See Spence, in Mag. Nat. Hist. Jan. 1830, p. 49. and Carus, Entdeck. einfacli. Herzen besch. Dlutkreis , fyc.)
The family EpiiEMERiDiE * Leach , comprises the well-known tribe of insects, ordinarily known under the name of May-flies, distinguished
* M. Pictet informs me that he considers the Isogenus Nubecula Newm. to be the Perla bicaudata Linn. ; but this is doubtful, as the Linnaean] description is too vague, and the Linnaean collection affords no decisive information.
* Bibliog. Refer, to the Ephemerid^e.
Clutius. Opusculum de Ilemerobio. 4to. Amsterd. 1634.
Swammerdam. Historie viid bet haft (Ephem.) Amsterd. 1675. — Ditto, in Book of Nature, pi. 13, 14, 15.
De Geer. Obs. sur les Ephem. in Mem. Acad. Sc. Paris, tom. ii. Sav. Etr. Schaffer. Das fligende Uferaas. 4to. Regensb. 1757, and in Abb. von. Ins. 3 b. Williamson, on Ephemeron Leukon, in Trans. Soc. Philadelphia, vol. v. 1802. Collinson, in Phil. Trans. 1746. (Eph. vulgata. )
N EUR OP TER A. — EPHEMEllIDiE.
25
Fig. 61.
membranous and almost obsolete mouth ; and the elongated articu¬ lated setae at the extremity of the body. The body is long, slender, and soft ( Jig . 61. l. Ephem. vulgata $ , with the tails cut partly off) ; the head small, transverse-trigonate ; the eyes large, nearly oval, and lateral, in the males of some species very large, and meeting on the crown of the head * * ; the ocelli are three in number, and placed in a triangle between the eyes; the anterior ocellus being often small, and the two lateral ones placed on peduncles (Jig- 61. 16. head of Baetis) : the antennas are small, and 3-jointed ; the two basal joints thick; the third forming a long slender seta : the clypeus in some species (Baetis, Jig. 61. 16.) is large, fleshy, and shutting over the mouth with
Curtis , in Taylor’s Philos. Mag. 1834. — Ditto, Brit. Ent. Dryander. Libr. Banks, sub Ephemera.
Stephens, Savigny (Egypt), Fabricius, 8fc.
* The males of Ephemera bioculata L., in addition to the ordinary eyes, have the head furnished with two short, thick, erect pillars, on the top of which another pair of large eyes are fixed. Mr. Curtis doubts whether this insect has four wings ; and the figure given by De Geer, vol. ii. tab. 18. f. 9., represents an insect with only two wings, although it has i: s head represented with pillared eyes. GeoflTroy’s figure, vol. ii. tab. 13. f. 4., has four wings, two anal setas, and two very large eyes. The insects which appear to me to accord with the Linnasan description, have four wings ; but the posterior pair are very minute, with only two longitudinal nerves. The nerves of the anterior wings are exceedingly delicate ; and between each pair of the longitudinal nerves, at the tip of the wing, there are two very short nerves uncon¬ nected with any transverse nerve. These characters will be sufficient for the form¬ ation of this species into a separate genus, which may be named Bracliyphlebia. It is perhaps equivalent to Stephens’s section a of Baetis, I lie Linnaean specimens are destroyed.
25
MODERN CLASSIFICATION OF INSECTS.
a thickened rib half way down the centre, and slit through the frontal half. As the life of these insects ordinarily extends but for a few hours, the parts of the mouth are almost obsolete, being minute, fleshy, and filled with fluid, so that their structure is not easily discernible. Latreille describes them doubtingly, as consisting of four short multi- articulate palpi, more slender at the tip. Mr. Curtis having examined living specimens, says that the parts of the mouth seem to consist of two large triarticulate ? palpi, with two compressed elongated sublinear lobes between them (maxillae, jig.6\. 2.), and a dilated labrum with two large divaricating fin-like lobes (palpi? jig. 61. 3.). Reaumur’s figure of the under side of the head (tom. vi. pi. 43. f. 1 1.), represents a space “ ou devroit etre la bouche et d’ou on ne fait sortir qu’une vessie, au dessous on voit quatre languettes charnues, dirigees vers la partie posterieure ; ” and Savigny has represented the parts of the mouth of a Baetis, in the great work on Egypt ; but it is impossible satisfactorily to make out their analogies. The thorax is oval and convex ; the prothorax small, narrowed in front, the mesothorax large ; the abdomen is elongate, narrow, of nine segments in both sexes, the terminal segments being longest, and gradually narrowed ; it is furnished at the apex, in both sexes, with two or three long, slender, multiarticulated filaments * ( jig. 61. 4. $ .), and in the males with four, two short setaceous articulated appendages, and two shorter straight ones, which are sometimes not exsertedf ; the wings are of unequal size, the anterior being much larger than the posterior, and elongate-trigonate, considerably reticulated; at rest they are generally carried erect ; the posterior pair are wanting in some species (Cloeon, Ephemera diptera Linn.). The legs are slender and simple ; the anterior pair, in the males being porrected, and greatly elongated, with the tibiae and tarsi appearing soldered together ; the basal tarsal joint being very minute ; the tarsi are 5-jointed, simple, and terminated in the fore legs of the males by two oval pulvilli ; in the four posterior legs the tarsi are short, 5-jointed ; the basal joint (in the males of E. vulgata), being shortest, and soldered to the tibia (so
* Latreille ( Hist . Nat. Ins. vol. xiii. p. 80. ) states that the males differ from the females in having the middle anal filament very short, whereas it is as long as the others in the females. This is the case in a species observed by Reaumur; hut in the true Ephemerae, the middle seta is nearly, but not quite, as long as the lateral ones
4 In Eph. vulgata 5? they have been overlooked by Curtis, but the extremities are distinctly exserted in my specimens. I have seen no species with three of these short appendages as described by Latreille, Ge?i. Cr. vol. iii. p. 3 84.
NEUROPTERA.
EPHEMERIDiE.
27
as to make the tarsi appear 4-jointed, as, indeed, they have been de¬ scribed by some authors), and terminated by a large oval pulvillus, and a single broad notched claw.
Dr. Leach formed these insects, in his MSS. (quoted by Stephens, Syst. Cat. p. 305.), into a separate order, named Anisoptera, from the unequal size of the wings.
Cuvier, followed by Dumeril, united them together with the Phry- ganese, into a distinct section of the order, termed Agnathes, from the rudimental structure of the mouth, destitute of jaws ; whilst Bridle united them with Libellula and Termes into a separate order, which he named Dictyoptera.
These insects have obtained their name Ephemera, from the Greek E <pt}/j.Epo£, diurnal, in allusion to the extremely short space of time* which they occupy as perfect insects. Their elegant flight in swarms (composed, as in the gnats, almost entirely of male insects) in fine afternoons, over or near water, alternately rising and falling, must have attracted the attention of the most incurious: in this operation the up¬ ward flight is produced by the repeated action of the wings ; but in descending, the wings are widely extended, as well as the tails. A few "hours previously, they had been the inhabitants of the water, from which, in the pupa state, they had crawled to the surface, where they cast off their pupa skin, appearing at first sight to be fully developed, with the wings extended to their full size (which state is termed by Mr. Curtis the pseudimago) ; they then make their way, flying with difficulty, to the shore, where they affix themselves to the trunks of trees, stems of rushes, walls, or even upon persons standing upon the bank, when they again cast off a very delicate pellicle, in which they had been entirely encased, and which remains, unchanged in form, attached to the objects on which they had stationed themselves : the skin, however, in which the wings had been enclosed, shrivels and curls up into a mass, hanging down at the sides of the thorax ; after this process, the wings, disengaged from the outer covering, assume a brighter appearance, and the tails grow to twice their previous length.
* De Geer kept Ephemera vespertina alive for eight days ; and Mr. Stephens mentions having kept specimens of Cloeon dipterum alive above three weeks. Had these individuals, however, been at large, and capable of pursuing their natural habits, I doubt not that their existence would have been as short as that of their companions. Dr. Franklin’s beautiful address, supposed to have been delivered by an “ancient Ephemera,” which had lived four hundred and twenty minutes, is one of the most profound lessons to humanity ever published.
28
MODERN CLASSIFICATION OF INSECTS.
In some specimens which I have reared, I have invariably found that the casting off of this pellicle takes place during the night. In some species, the operation of shedding this pellicle takes place immediately after flight, and is so quickly performed, that the whole operation does not exceed three minutes; immediately after which the insect again takes wing. (Davis, in Ent. Mag. vol. ii. p. 822.) I have observed in one instance, at least, that the insect remained in the pseudimago state upwards of twenty-four hours. In consequence of this pecu¬ liarity, these insects have been described as undergoing a quadruple metamorphosis.* After coupling has taken place, the females deposit their eggs in a mass, and which they drop into the water. This being the only operation which the perfect insects are able to perform, they die as soon as it is accomplished.
Notwithstanding the dangers to which the eggs, larvae, and pupae are constantly exposed, from the attacks of fishes and predaceous aquatic insects, the number of specimens which arrive at the per-
* Swammerdam asserts of the species which he observed, that the males only un¬ dergo this second moulting. I can affirm that in E. vulgata both sexes are subject to it.
This power of flight by the insect, previous to attaining its final form, is perfectly anomalous; and if we were to adopt the opinion expressed by Mr. Newman (Ent. Mag. vol. iii. p. 19.), that the pseudimago state of the May fly is analogous to the pupa of the bee, or the chrysalis of the butterfly, it would necessarily follow that the state in which rudimental wing-covers are developed, preceding the pseudimago state of the former, is analogous to the last stage of the larva of the latter insects. But Mr. Newman has shown that he is aware of the fact, not only that the dragon fly, on becoming a perfect insect, quits a double skiu, the interior of which is analogous to the external pellicle of the pseudimago, but also that butterflies, moths, and gnats, “ which do not retain the skin of the previous state, on entering the quiescent state, retain two distinct coverings ; ” the interior being a soft pellicle, which must have been observed by all who have paid any attention to the rearing of Lepidoptera. But Mr. Newman further contends that the pupa of a bee or beetle is enveloped in only a single skin; whilst the flesh fly, &c. (or the insects which undergo the true coarctate metamorphosis, that is, “ on assuming the quiescent state they retain the last cuticle of the previous state,”) cast off two skins on becoming perfect insects. Now, both those assumptions are contrary to fact as well as to analogy, since it is certain that the beetles, after quitting the pupa skin, are at first enveloped in a thin pellicle, like the May-fly, and which I doubt not is general, and to be found in the bee, as well as the beetle, if sufficient careful researches were made for it ; whilst, at the same time, we are warranted in considering that the real pupa of the flesh fly is likewise inclosed in a similar membrane, so that the latter insect, on arriving at the perfect state, casts three, and not two, skins ; namely, the hardened ultimate larva skin, the real pupa skin, and the pellicle analogous to the pseudimago skin of the May fly, which, from its firmer consistence is retained longer by the last-mentioned insect. If this be a cor¬ rect view of the real nature of the pseudimago state, there will be no grounds for rejecting the Linnaean definitions of metamorphosis.
NEUROPTERA. - EPHEMERIDjE.
29
feet state is sometimes so immense, that the swarms of one species with white wings (E. albipennis) has been compared to a fall of snow; whilst, in some parts of Europe where they abound, it is the custom to collect their dead bodies into heaps, and use them for manure. The fishes at such time eagerly wait for them ; and so great are the numbers which fall into the water, that the fishermen call them manna.* They are well known to the angler as excellent baits for trout. \ They are also a favourite food of the smaller dragon flies. If, however, the life of these insects in their perfect state is so short, it is of much greater duration in the preparatory states, extending at least, in some species, to two or three years. During this pe¬ riod, they are inhabitants of the water, in which they ordinarily hide themselves, during the day, in the earth, under stones, or in horizontal burrows, divided internally into two canals, each having a separate opening externally, and uniting internally at the extremity, so that the insect can crawl in at one hole and out of the other, without being obliged to make the awkward turn it would have to do, if in a straight hole : these burrows are formed in the earth of the sides of the stream, or standing water, and which circulates freely in them. It is affirmed by some authors, that the larva feeds upon the mud at the sides of its retreat (Hist, of Insects, p. 106.). Swammer¬ dam, who dissected these larvge, always found mud within the stomach and the great and small intestines. It is most probable, therefore, that when the larva has assimilated the decaying vegetable matter therein contained, the earthy particles are discharged. The larvae bear a considerable resemblance to the imago in their general form, but are easily distinguished by their long multiarticulate antennae ; the want of ocelli ; the presence, in some species, of two corneous ap¬ pendages in front of the head, considered as mandibles, and more
* I must refer to Kirby and Spence’s Introduction for various particulars relative to the almost incredible appearance of the swarms of these insects upon certain occasions.
•f- Out of forty-four species of insects given by Mr. Ronald in his Fly Fisher's Ento¬ mology, eighteen belong to the present family. Amongst the smaller species, the pseud- imago and imago are known under different names, d he various kinds of duns are all in the pseudimago state, the name evidently applying to their duller colour. The green drake is the pseudimago, and the grey drake the imago of E. vulgata $> . See further Sir H. Davy’s Salmonia, and the late editions of Isaac Walton. The females, filled with eggs, are most eagerly seized by the fish ; the males, inflated with air, offer them but little nourishment, and are called bastard May flies by the Oxfordshire fish¬ ermen. It is rarely that the females are found in the swarms hovering on the water.
30
MODERN CLASSIFICATION OF INSECTS.
particularly by the possession of a row of thin plates on each side of the abdomen, ordinarily united in pairs by their bases, and which are a species of external false branchiae or gills, in which the tra¬ cheae are extended, and ramify ; thus serving as organs of respiration, as well as assisting in locomotion by their constant undulatory mo¬ tion : the abdomen in the larva is terminated by three setae, which is the case, not only in those species which have three filaments in the imago, but also in those with only two tails. I have observed that these setae acquire a greater length at each moulting.
Those species which reside in burrows seldom quit their retreats ; whilst the smaller species, which live at large in the water, are much more active, and have the body of a firmer consistence than the others. The pupa differs only from the larva in having the rudi- mental wing-covers more conspicuous at the sides of the meso- and meta-thorax.
The investigation of the preparatory stages of the different species of these insects, will be sufficient to prove the necessity of their separation into even more genera than have hitherto been proposed for them. The pup® of several species are represented by De Geer and some other authors : the larvae, however, are not figured, but we may consider them as similar in character to the pup®, from which they differ only in the absence of rudimental wing-covers. In the species to which the generic name has been restricted by recent authors (E, vulgata, &c.), the pupa (my fig. 61. 5., and De Geer, tom.xxi. tab. 16.), is distinguished by a transverse-quadrate prothorax as broad as the head, a very gibbous meso-thorax, a head of rather small size, with two short horns in front, and two long, acute, slightly recurved mandibles, originating at the sides of the mouth, and being as long as the head (fig- 61. 6. head sideways). Considering the rudi¬ mental nature of the mouth of the imago, it is surprising that no one has hitherto described' the real structure of the mouth, in the preparatory states. Reaumur has attempted it, but his figures are so rude and insufficient, that no idea can be gleaned as to their true structure ; Swammerdam, also, passes them over undescribed. In the pupa of E. vulgata, the upper lip is of moderate size, with the anterior angles rounded off, and ciliated ; it is flat, and quite membranous (fig. 61. 7.) ; the mandibles (fig. 61.8.) are horny, armed with several teeth within, near the base (fig. 61. 9.), which is dilated into a flattened molary plate ; whilst the upper angle of the mandible
NEUROPTERA. - EPHEMERIDiE.
31
is produced into the long curved horn above described. The max- iliac {Jig. 61. 10.) are small, membranous, curved, pointed at the tip, and internally setose ; the maxillary palpi do not extend beyond the front of the head; they are 4-jointed, the basal joint being very
a
short; the lower lip {Jig. 61.il.) is very large and membranous, co¬ vering the underside of the mouth; it is quadrilobed (yfy. 61 . 12.), and furnished within with a broad tongue {Jig* 61. 13.), of which the anterior angles are produced and pilose ; the labial palpi are broad and 3-jointed; the antennae are about twice the length of the head, multiarticulate, and ciliated ; the eyes are large and rounded; the legs are short, broad, and very much compressed ; the tarsi 2-jointed, with a terminal hook {Jig. 61.14.) ; the abdomen is 9-jointed, the terminal segments being the longest : of these segments, the six basal ones are furnished on each side with a pair of elongated rather narrow gills, the edges of which are furnished with long, nar¬ row filaments {Jig 61.15.), through each of which an air-tube ex¬ tends to the tip ; the air-tubes from each contiguous pair of filaments uniting near the base, and then running to the large tube which tra¬ verses the centre of each gill. Each of these pairs of gills are united together at the base, so that in the whole the insect has twenty-four gills. The insect, of which the history is figured by Schaffer {AblmndL vol. iii. pi. 1.), appears to be an Ephemera, with four wings, and three tails, the larva of which forms burrows in the earth ; but it is impos¬ sible, from his figures, to ascertain either the species or the real cha¬ racters of the preparatory states.
In a small species figured by De Geer {Mem. tom. ii. tab. 17. f. 11 — 16), having four wings and three tails, the eyes of the male being very large and much elevated, and which is regarded as the E. vespertina (which Mr. Stephens introduces into his second section of the genus Ephemera), the head of the pupa is unarmed ; the an- tennm longer ; the legs and anal setse longer and more slender ; the seven basal abdominal segments are furnished on each side with a pair of oval, flat, membranous gills, each terminating in a long point, and not provided with long marginal filaments {Jig* 61. 19.), The insect figured by Rosel {Ins. Belust. tom.ii. tab. 12. f. 1, 2.) is evidently iden¬ tical, in the structure of the pupa and imago, with these figures of De Geer. This and the allied species may, perhaps, from the consider¬ ation of the variation of their preparatory states, be advantageously separated as a distinct genus, to which the name of Leptophlebia may
32 MODERN CLASSIFICATION OF INSECTS.
be applied, in allusion to the delicacy of the veins of the wings, which are moreover destitute of the numerous transverse veins near the pos¬ terior base of the fore wing, so conspicuous in E. vulgata.
The pupa of another species, belonging to the genus Baetis, is figured by Ee Geer (vol. ii. t. 18. f. 1 — 4.), and is remarkable for the broad flat head, with short antennae, and large eyes ; the prothorax is very broad and flat; the legs short, with the femora greatly dilated and compressed ; and the seven basal abdominal segments furnished on each side with a broadly oval gill, terminating in a point ; the six basal ones on each side being further furnished with numerous long floating filaments, representing the other gill (fig* 61. 18.) ; the tails are very long, and not fringed. My specimens (Jig. Si. 17.) have the head and prothorax considerably broader than they are figured by De Geer, but in all other respects they correspond : in one of these which I dissected, I found the labium very large, completely covering the other parts of the mouth ; the mandibles being small, but furnished at the base with a molary plate, as in the pupa of E. vulgata.
Messrs. Goring and Pritchard (Nat. Hist. Obj. for Microscope, 1829, pi. 1.) have figured the pupa of a species which they named E. mar- ginata; but their figure of the imago represents it as 2-winged and 2-tailed, thus belonging to the genus Cloeon. The head of the pupa (Jig. 61. 20.) is small, scarcely more than half the breadth of the meso- thorax ; the antennas as long as the body, about 24-jointed; the ter¬ minal joints being gradually elongated ; the legs long and slender, with 2-jointed tarsi ; the five basal abdominal segments furnished on each side with a pair of flattened membranous gills, each being very short (especially the basal one in each pair), the posterior one in each pair being of an elongated oval transverse form : the sixth abdominal seg¬ ment has on each side a single larger gill ; the three apical setae are long, multiarticulate, and finely setose ; the central setae (as the pe¬ riod for assuming the perfect state approaches) becomes more trans¬ parent ; whereas the two exterior ones exhibit the two tails of the perfect insect inclosed in them. This pupa feeds on minute aquatic larvae, as well as on vegetables ; the rapidity of its motions is astonishing, employing the six double paddle-like gills as oars, and for the purpose of balancing itself, and the posterior pair as paddles ; it likewise possesses the power of leaping or springing in the water to a considerable distance. I have observed these pupae to possess the power of darting both forwards and backwards with equal rapidity. This insect in its earlier larva state (in which the thoracic and basal
NEUROPTERA. — EPIIEMERIDJE.
33
abdominal segments arc "of equal size) has formed the subject of a valuable paper upon the circulation of the blood, by Mr. Bowerbank. ( Ent . Mag. vol. i. p. 239.)
The larvae and pupae figured by Rosel (Ins. Belust. tom. ii. tab. 12. f. 3, 4.) seem, at least so far as they can be determined from the figures, to be similarly constructed to the pupa figured by Goring and Pritchard; the head being of moderate size, and the anal filaments deeply fringed ; but the imago (fig. 6.) is represented as possessing four wings and two tails : so that either the genus Baetis, as even now restricted, must comprise several distinct types, or Rosel must have erred in giving four wings to his imago.
The species which afforded Swammerdam materials for his admi¬ rable history of the Ephemera, abounds to an astonishing extent in the rivers of Holland and Germany, and makes its appearance regu¬ larly, in swarms, at the mouths of the Rhine, Meuse, Wael, Leek, and Ysel, during three succeeding days, about the feast of Olophius and St. John. It is considerably larger than E. vulgata, with four wings and two long hairy tails ; and has been named E. Swammerdiana by Latreille, in honour of its historian. It clearly belongs, however, to a distinct genus ; its larva burrowing in the ground, with short broad legs, and its head cornuted (see tab. xiv.) : the first abdominal seg¬ ment is not furnished with gills, but each of the six succeeding seg¬ ments has a pair on each side ; the posterior in each pair being very small, and termed by Swammerdam rowing fins. The male pupa differs from the female in the larger size of the head, and especially of the eyes.
Reaumur ( Memoircs , tom. vi. Mem. xii. tab. 42 — 44.) has given numerous details of a large species, which in several material respects differs from any of the foregoing ; it has four wings, and three tails, which in the female are of equal length, but in the male the central one is not half the length of the abdomen : the abdomen of the male is armed at its extremity beneath with a pair of straight appendages of considerable length, in addition to the pair of articulated forceps ; the meso- and meta-thoracic spiracles are of large size ; the female deposits her eggs in two long oval masses. The larva burrows in ground at the sides of the rivers, and has short broad legs, the man¬ dibles are greatly elongated, curved, and armed along the under surface with two rows of small points, and an apparently articulated hook at the tip ; and the gills are of an elongated kidney shape, narrowed
vol. ir.
D
MODERN CLASSIFICATION OF INSECTS.
31-
towards the extremity with broad short ciliae, and a large air-tube running down the centre of each ; the two plates on each side of the segment are of nearly equal size. Reaumur has also represented (pi. 45.) another pupa, with simple head and long legs, and in which the gills form a large and broad plate, which is ordinarily folded so as to appear like two narrow plates. He has not described the imago of this species. In the following plate, he has figured two other kinds of pupae, in one of which (whose imago is not given) the mandibles are very broad, porrected, and dentated, and the gills formed as in the pupa of E. vulgata. The other species appears to be a Cloeon like Goring and Pritchard’s figure, but the gills of the pupa are represented like those of E. vulgata.
The family Libellulida; *, comprises an extensive and beautiful group of large-sized insects, well known under the common names of
* Bibliogr. Refer, to the Libellulid^e.
Bartram. On the Dragon Fly of Pensylvania, in Phil. Trans, vol. xlvi. 1750. Muller. Enura. ac Descr. Libell. Agri Friedrichsd. Nov. Act. Nat. Cur. tom. iii. 1767.
Vander Linden. Agriones Bononienses Descr. 4to. Bononiae, 1820. — Ditto, JEshnas Bonon. Descr. 4to. Bon. 1820. — Ditto, Monogr. Libell. Europ. Specim. 8vo. Brux. 1825. — Ditto, Notice sur une Empreinte d’lnsecte.
Hansemann, in Wiedemann, Zool. Mag. 2 band. (Europ. Agriones.)
Van der Hoeven, in Ann. Sc. Nat. 1825. (Neuration of Wings).
Guerin. Mag. Zool. No. 15. (Agrion fnlgipennis).
Bridle, in Ann. Soc. Ent. France, 1833. (Month of Libell.). — Ditto, in Exped. Scient. de Morea.
Newman, in Entomological Magazine, vol. iv. and v.
Rathlte. De Libellularum Partibus Genitalibus. 4to. Regimont. 1832. Fonscolombe, in Ann. Soc. Ent. de France, 1837, 1838.
Charpentiir. Horas Entomologicae.f I^each. Zoological Miscellany (Petalura).
Latreille. Hist. Gen. Crust, et Ins. vol. xiii.
Kirby, in Linn. Trans, vol. xiv. (Agrion Brightwellii.)
Harris. Exposition of English Insects.
Eversmann. Libell. Wolga. Bull. Moscow, p. 239.
JDe Selys Longchamps. Catal. des Lepidopt., and Tableau dcs Libellul. de la Bel¬ gique. Liege, 1837.
Drury, Savigny (Egypt), Olivier (Enc. Meth.), Fabricius, Perty.
f M. Charpentier has shown me a thick folio volume of drawings of the different species of this family, of which he is preparing a monograph.
NEUROPTERA.
L I BELL UL I DTE.
35
Fig. 62.
horse stingers and dragon flies, the first of which is founded upon a vulgar error ; the second is more fancifully correct, as the insects, both in their appearance and voracious habits, are certainly more entitled to the name of dragons than that of “ demoiselles,’’ as they are called by the French. The body is very much elongated, narrow, and nearly linear ; the head large, semiglobose, or transverse-subtrigonate ; the thorax thick and deep; and the abdomen long, with inarticulate apical appendages ( fig . 62. l. Libellula Scotica) ; the antennae are short, and very slender, with from five to eight joints, of which the two basal ones are the thickest; the terminal ones being subulate (Jig. 62. 7.) ; the eyes are very large, uniting on the top of the head (Jig. 62. 2. head of L. depressa ; the figures 62. 2. to 13. represent details of this species). The upper facets are of a larger size than the lower ; Mr. Ashton has communicated a memoir upon this structure of the eyes, in these and some other insects, to the Entomological Society. The ocelli are three, the two lateral ones placed at the sides, and the an¬ terior one in front of a vesicle on the forehead. The mouth is well described by Latreille, as being “ larvatum,” or masked ; the lips (es¬ pecially the lower one) being of a large size, and the palpi not elon¬ gated beyond the mouth (Jig. 62. 2.); the upper lip is transverse, with the angles rounded off ; the mandibles (Jig. 62. 3.) are horny, very thick and powerful, and multidentate ; the maxillae (Jig. 62. 4.) are more elongated, dilated in the centre, armed with strong terminal teeth, and destitute of an external lobe, the place of which is supplied by the max¬ illary palpus, which is short, thick, and hirsute, apparently only shortly articulated at the base, and terminated by an acuminate point; the lower lip (Jig. 6 2.5.) is singularly constructed (the true labium, x> , arising in 7Eslma,from a distinctpiece (fig.62.\&. x, which is obsolete in Libellula),
d 2
36
MODERN CLASSIFICATION OF INSECTS.
and consisting of three lobes, of which the centre one is deeply cleft in Agrion * (Jig. 62. 15.), but entire in 2Eshna and Libellula xx ; the two lateral lobes are flat and horny, with an articulation at the base, and of a very large size in Libellula (Jig. 62. 5.), meeting and slightly crossing each other in front of the middle lobe; at the inner anterior angle of these lateral lobes is a small horny point, accompanied, in 2Eslma( Jig. 62. 14.) and Agrion (Jig. 62. 15.), by a short inarticulated appendage.f Within the mouth, the lingua (Jig. 62.0.), or the palatum of Latreille, appears distinctly of a large size, leathery, vesicular, and villose. The prothorax is reduced to a very short, and small piece; whilst the meso- and metathorax (not the mesothorax alone, as stated by Latreille, Gen. Cr., vol. iii. p. ISO.), are large, subcylindrical, ver¬ tically compressed, and oblique ; the wings are large, of equal size, and exceedingly closely reticulated ; the anal angle of the posterior pair being often acuminated in the males. Van der Hoeven has pub¬ lished a short note relative to the distinctions existing in the neuration of the wings of iEslma, Libellula, and Lindenia, consisting of a small triangular space inclosed by strong nerves near the base of the fore wings. A careful comparative examination of the nerves of the dif¬ ferent species will clearly prove its existence, not only in the fore wings, but also in the posterior wings, of all the Libellulides, with this difference, that in the posterior wings, a supplemental piece, forming the anal angle, is added, so that the cells, analogous to those of the anal angle of the fore wings, are pushed out of place. When at rest, they are either horizontally extended or carried erect over the abdomen ; the legs are short, slender, and armed with numerous slender spines ; the tarsi are 3-jointed, the basal joint being the smallest (Jig. 62. 8.) ; the abdomen is long, and either lanceolate-depressed, or subcylindrical, armed at its extremity with folioles or hooked appendages, variable in form, both in the sexes and species. In the males, the organs of ge-
* By this name I here more especially mean L. virgo, which is the true type of Agrion Fab. ; although Leach injudiciously formed it into the genus Calepteryx, retaining Agrion for other insects.
•f The singular construction of the labium renders the analogical investigation of its parts very difficult : we may regard these three lobes as forming a trilobed ligula, in which case, however, the horny point at the internal angle of the lateral pieces must be regarded as appendages, and not as palpi, as Latreille regarded them ( Gen. Crust., vol. iii. p. 180.), because the labial palpi never arise from the extremity of the lateral lobes of the ligula. In such case, perhaps the outer part of the maxilla would rather represent the galea, the palpi being obsolete. On the other hand, we may, with M. Bridle (Ann. Soc. Ent. de France, tom. ii. p. 343.), regard the outer lobes as enormously dilated labial palpi.
NEUROPTERA.
LIB ELLUL I DiE.
37
neration have been ordinarily described as of very complicated struc¬ ture, and as occupying the under surface of the base of the abdomen. They have been described in detail by De Geer, Reaumur, and espe¬ cially by Rathke. Burmeister, however {Manual of Enlomol., p. 218.), asserts that these organs are only those of excitement, and that the real male organs are placed within the ninth # abdominal segment, in an aperture closed by two valves on the ventral surface of this seg¬ ment {fig. 62. 9.).
These insects are distributed over all parts of the globe ; few, how¬ ever, exceed in beauty or size the inhabitants of our own country ; a peculiarity common to other aquatic tribes.
The elegant appearance of these insects on the wing ; their varied colours, in some, of a rich blue (“the beautiful blue damsel-flies ” of Moore); their delicate gauze-like wings, and their rapid flight, must have attracted the attention of every one. During the hottest days of summer they are to be observed darting backwards and forwards in the air, especially in the neighbourhood, or over standing water, where they find an ample supply of food in the myriads of insects which are there generated. The admirable adaptation of the form of the various parts of the body, namely, the powerful structure of the mouth, large size of the eyes and wings, and length of the rudder-like abdomen, has been happily treated by Mr. Newman {Ent. Mag., vol.ii. p.67.). There is considerable diversity in the colours of the sexes of some of these insects, the males having the abdomen of a lead blue, whilst the females are rich yellow-brown. In some of the Agrionides, the males, which fly over the water in swarms, are of a rich blue, with black wings, whilst the females are fine green, with colourless wings. (See also Schelver in Weidemann’s Arcli. Zool. , st. 2.) The partiality of these insects for various colours is noticed by Mr. Patterson {Ent. Trans ., vol. i. p. 82. app.).
These insects live in the perfect state a considerable period. In the summer of 1833, I noticed, during several weeks, a solitary specimen of Anax formosa hawking over a small pond on Wands¬ worth Common ; and, from the rarity of the species, I have no doubt that it was the same insect. Mr. Ingall has mentioned to me an in¬ stance in which a specimen, destitute of a head, and of which the
* It is in the eighth, and not the ninth, abdominal segment that these valves are placed. Burmeister’s mistake has evidently originated in the apparent articu¬ lation of the basal segment.
38
MODERN CLASSIFICATION OF INSECTS.
abdomen was suspended only by a small portion of membrane, flew to a considerable distance after a pin had been passed through the thorax for six hours.
The pairing of these insects is effected in a singular manner ; the male seizing the neck of the female by means of the hooks at the extremity of the body, and thus for a time the two insects fly about in a line, at length, however, the female curves the body, sothat the under side of its extremity is brought into contact with the organs placed at the base of the abdomen of the male. Burmeister, however, asserts that these proceedings are but preliminary, and that copulation takes place in the ordinary manner (and see Drury , vol. i. p. 114. 2d edition).
The female, after impregnation, deposits her eggs in the water, into which she intrudes the extremity of the abdomen so as to attach them to the stalks of plants, 8cc. ; sometimes even, according to an ac¬ count with which I have been favoured by Mr. Patterson, the female Agriones descend to a considerable depth below the surface. (See Ent. Trans ., vol. i. p. 82. app.) I have observed these females, in the act of oviposition, beat their tails upon the surface of the water with rapid succession, until the eggs form a mass like a bunch of grapes.
In their preparatory states, these insects reside in the water, and have to a certain extent a resemblance with the imago. The body is more or less elongated, according to its form in the perfect state ( Jig . 62. to. pupa of L. depressa, fig. 62. 16. pupa of Agrion virgo) ; the eyes are of moderate size; the ocelli wanting; the antennae filiform (not setaceous, as in the imago), and 7-jointed ( fig . 62. 1 3.— fig. 62. 18. antenna, and fig . 62. 19. tarsus of pupa of Agrion virgo) ; the parts of the mouth are not dissimilar to those of the perfect insect*, with the exception of the lower lip, which is formed into a remarkable mask¬ like elongated appendage, which completely shuts in the mouth, to which, when unemployed, it is closely applied (as in fig. 62.10.); on extending it, however (as in fig. 62. n. and fig. 62. 12., seen from be¬ neath), it is found to consist of, 1st, a basal piece (or cardo) by which it is united to the under side of the head; 2ndly, an elongated piece di¬ lated in front, and concave beneath, so as to close upon the former ;
* In the pupa of L. depressa ( fig. 62. 10.), the labrum is transverse, with the lateral angles rounded off ; the mandibles triangular, horny, with several small apical teeth ; the maxillae are slender, with five acute apical teeth, and an inarticulated palpus, of equal length with the maxillary lobe ; and the tongue distinct, as in the imago. The mandibles and maxillae are much more strongly toothed in the pupae of the /E hnae.
NEUROPTERA. — LIBELLULID7E,
39
and 3dly, a pair of transversely triangular pieces, toothed along the inner margin, and articulated at the outer angles of the preceding piece, so as to be capable of being widely opened. The use of this curious in¬ strument, of which the insect has the power of opening and closing the various parts with the greatest facility, is to seize its prey, which consists of other aquatic insects, and even of small fishes (Mag. Nat. Hist., No. 28.), which are immediately brought within reach of the jaws. The parts of which this organ is composed are analogous in their general structure of the different groups, to those composing the lower lip of the imago ; thus, in Agrion virgo ( Jig . 62. 15. labium of imago, ^.62. 17. labium of pupa), the central piece is deeply notched, and the lateral pieces are terminated by four acute spines.* (SeeBrulle, in Ann. Soc. Ent. cle France , tom. ii. p. 343.) The basal part, by which this organ is attached to the head, appears to represent the mentum, the following more elongated piece, the labium (ligula), and the two terminal parts, the labial palpi. The sides of the meso- and meta-thorax are soldered together, and dilated into a large lateral plate.
The mode of respiration in these insects during their preparatory states is singular. The abdomen is terminated, in the larger species, with five corneous plate-like appendages of unequal size, and conical form, three being much larger than the others, which the insect has the power of separating or bringing into contact, so as to form a py¬ ramidal tail. On opening these pieces, a valve, previously closed by three membranous plates, is opened, and a quantity of water passes into the body, when they are closed ; shortly afterwards, however, the water, from which the insect has extracted the oxygen by the as¬ sistance of various internal organs communicating with the tracheae, is discharged with considerable force to the distance of two or three inches, by the action of an inclosed organ, which Reaumur calls “ le tampon.” This discharge has the effect of giving a progressive motion to the body.
In the 2Eshnae the pupa has the middle plate at the extremity of the body truncated, and armed with two minute points. A memoir by Suckow, on the respiration in fEshna grandis, is noticed in the Bulletin Sci. Nat., June, 1829.
* In the genus Agrion (L. Puella), the mask of the larva has a single projection on the upper edge of the mentum ; in Lestes a double projection exists ; and in Ca- lepteryx (L. virgo) it has a triangular excision at the tip, terminating in two points.
( Stephen's Brit. Ent., vol. vi. p. 78.)
D 4
40
MODERN CLASSIFICATION OF INSECTS.
In the Agrionides the abdomen of the larvm and pupae are termi¬ nated by three narrow elongated plates ( fig . 62. 19..
The preparatory states of these insects last for ten or eleven months ; during which, according to Latreille, the skin is cast several times (but Drury states that he had not observed this shedding of the skin). When nearly arrived at the period for assuming the perfect state, the wing-cases become detached from each other, and exhibit traces of the mesh-like appearance of the inclosed wings. The pupa creeps up the stem of some aquatic plant or stone, when about to assume the imago state; after a few hours remaining in this situation, it attaches itself as firmly as possible to the spot by means of its ungues, the head being uppermost ; the skin of the thorax then slits, and the in¬ closed pupa gradually disengages itself, throwing its head backwards ; which position it retains for a considerable period, being retained in its situation by the terminal rings of the abdomen, which remain still within the pupa skin ; it then gains an erect position, draws out the remainder of the abdomen, and remains stationary for an hour or two, until its pendant wings have assumed their full size and consistence.
Rosel has given figures of various species of Libellulos, iEshnae, and Agriones, in their different states {Ins. JBelust ., vol. ii. ; Ins. Aq., tab. 2 — 11.) ; De Geer also (vol. ii.) ; Reaumur ( Memoires , vol. vi.) ; Lyonnet {Mem. Posth ., pi. 1 8.) ; Guerin {Icon. R. An. Insectes ) ; Frisch (vol. i. pt. 8. pi. 8.) ; Swammerdam (tab. 12.); and Drury (vol. i.), have given figures and descriptions of the preparatory states of various species of dragon flies.
Fabricius formed these insects into a distinct class (order), named Odonata.
Dr. Leach has divided them into two families ; but it appears to me to be more natural to consider them constituting one family, cor¬ responding with the Linnaean genus, divisible into two subfamilies. The exotic species do not offer any material peculiarities, if we except some species of tropical Agrionides, which have the abdomen nearly six inches long, and very slender and cylindric.
Dr. Leach also, many years ago, divided these insects into several ad¬ ditional genera, which have not been adopted by foreign writers; but I have little doubt that corresponding characters would be found to distin¬ guish the genera of Libellulides,in the preparatory stages, as well marked as those which I have noticed above in the genera of Agrionides.
NEUROPTERA.
MYRMELEONIDiE.
41
The family Myrmeleonid^e * comprises a considerable number of large and handsome insects, none of which are ascertained to be natives of this country, and which are known, in their larva state, under the name of ant-lions (fourmilions). The body of the perfect insect (< fig . 63.1. Myrmeleon formicarium, natural size, Jig. 62. l — 19.
Fig. 63.
represent details of this species) is long and slender ; the head small, with prominent lateral eyes, and destitute of ocelli ; the antennse longer than the head, multiarticulate, and thickened at the tip ( fig . 63. 2.) ; the upper lip is rounded at the sides, and attached to the head by a distinct clypeus ; the mandibles ( jig . 63. 3.) are horny, curved to the tip, with a strong tooth below the internal apex ; the maxillse {Jig. 63. 4.) are elongated and bilobed ; the inner one compressed and ciliated ; the external lobe or galea biarticulated ; the maxillary palpi slender, short, and 5-jointed ; the labium {Jig. 63. 5.) is large and square, arising from a narrowed mentum, and furnished with a pair of very long labial palpi, arising from the base
* Bibliogr. Refer, to the Myrmeleonidhs.
Percheron. Larva of Myrmeleon, in Guerin Mag. Zook, pi. 59.
Poupart. Hist. Formicaleo, Acad. Reg. Paris, 1704.
Latreille. Genera Crust., &c., vol. iii. p. 191.
Westwood, in Drury, new edition. (Euptilon.)
King. Symbolee Pbysicae (many sp. of Myrmeleon figured).
Guilding. Generic Cbar. of Formicaleo, with two new sp. in Linn. Trans., vol. xvi.
— Ditto, on Ascalaphus, in ditto, vol. xiv.
Schaeffer, on Ascalaphus, 4to. Regensb. 1763, and in his Abhandl., 2 band.
A. Blanchard . Note sur 1* Ascalapli. Italic, in Bull, d’ Hist. Nat. Soc. Linn. Bor¬ deaux, No. 1 .
Argelini (in Biblioteca Ital., tom. xlvii.) Ascalafi Italiani con Nuova Specie. Newman, in Ent. Mag., No. 24. (Stilbopteryx.)
Drury, Charpentier, Fabricius, Donovan , Ac.
42
MODERN CLASSIFICATION OF INSECTS.
of the labium, and 3-jointed ; the basal joint being very short, and the other two of equal length, being nearly as long as the antennae; the internal lingua is distinct and membranous ; the prothorax is smaller than the head, and transverse ; the two other segments form an oval mass ; the wings are large, and densely reticulated, and often coloured, with a strong vein, which is furcate at about one fifth of the length of the wing from the base ; they are of nearly equal size, and are deflexed at the sides of the body when at rest ; the pos¬ terior pair not being folded ; the legs are of moderate size, with 5-jointed tarsi {Jig.b 3.6.); the abdomen is very long and cylindric, often terminated by a pair of long slender inarticulated appendages.
These beautiful insects, in the delicate reticulation of their wings, vie with the dragon flies, whilst their habits render them equally interesting ; it is, however, in their larva state, that they have at¬ tracted the greatest share of attention, as in the perfect state they fly but little, keeping during the day amongst the leaves of trees and plants, and coming abroad only at dusk ; indeed, Mr. Guilding states that after a long-continued search he never found a single imago in a state of liberty, although the larvae swarmed in St. Vin¬ cent’s, so successfully are they secured from every enemy by their peculiar mode of resting, and the favourable colour of their bodies.
The larva * is of a form totally unlike the imago, being short, thick, and fleshy {Jig. 63. 9.) ; the sides furnished with numerous bundles of short rigid hairs ; the head and prothorax narrow ; and the meso- and meta-thorax and abdomen forming a very large oval mass, so as to bear a considerable resemblance to a spider ; the head is oblong, with six tubercular eyes on a short footstalk {Jig. 63. 13.) on each side ; the head is attached to the prothorax by membrane capable of great distention and motion ; the antennce are very short, slender, and mul- tiarticulate, arising from a thickened base {Jig. 63, 14.); the mandi¬ bles are longer than the head, very slender, and curved, forming a pair of toothed calippers, wherewith the insect seizes its prey. On the under side they are grooved, and within this groove the maxillae, which are still more slender, are placed, and in which they play backwards and forwards ; there appear to be no rudiments of maxillary palpi ; the lower lip is short, and furnished with a pair of 4-jointed palpi, of which the basal joint is large and ovate, and the three terminal joints slender ( Jig . 63. 10. represents the under side of the head of the larva,
* Donovan ( Nat. Misc., pi. 139.) has described the larva as an apterous female.
NEUROPTERA.
MYRMELEONIDiE.
43
a being the labial palpus, d the mandible, and c the maxilla in situ; and jig. 63.ll. represents the maxilla partially, and jig. 6 3.12. entirely, extracted from its groove in the mandible); the legs are long and slender, the two anterior pair being directed forwards ; but the posterior pair are shorter and stronger (jig- 63. 15.), so affixed to the body that they are not able to assist in progression, but are constantly employed in drawing the insect backwards, which is, in fact, its only motion; the ungues being much stronger than in the anterior legs ; and the tarsus (jig- 63. 15. e.) soldered to the tibia (jig. 63.15. d.), whereby greater power is given the limb.-* This peculiarity has not been previously noticed. This formation, together with its slow movements and its carnivorous habits, renders the construction of a snare necessary for the support of the insect. Some larvae of the common species, M. formicaleo, which I brought alive to this country from France, afforded me ample opportunities for watching their pro¬ ceedings ; and of which I have published a notice in Mag. Nat. Hist., Nov. 1838. It is in very fine sand that the larva makes its pitfall. When placed upon the surface, it bends down the extremity of the body (as in jig. 63. 8.), and then pushing, or rather dragging, itself backwards by the assistance of its hind legs, but more particularly of the deflexed extremity of its body f ; it gradually insinuates itself into, and beneath the sand, constantly throwing off the particles which fall upon, or which it shovels with its jaws or legs upon its head, by suddenly jerking them backwards,
“ Ossaque post tergum magnae jactata parentis.”
Proceeding in this manner, in a spiral direction, it gradually dimin¬ ishes the diameter of its path, and by degrees throws so much of the sand away, as to form a conical pit, at the bottom of which it then conceals itself, its mandibles widely extended, being the only parts that appear above the surface j: (jig- 63. 7. a small pit- fall) ; with these, any luckless insect that may happen to fall down the hole is immediately seized and killed. When the fluids of the victim are exhausted, the ant lion, by a sudden jerk, throws the dry carcass
* In the fore leg the tarsus is articulated ( Jig. 63. 9- e. )
4 Reaumur states that it is aide to creep almost as well when its legs are all cut off as when present, the abdomen being the chief means by which its motions are effected.
| Mr. Guilding states that those larvae which dig pitfalls are furnished with antennulae (above described), which are held erect, and are doubtless useful in in¬ dicating the approach of their prey by the falling of the sand ; in the larvae of the Ascalaphi they are wanting or obscure.
MODERN CLASSIFICATION OF INSECTS.
44
out of the hole; should, however, the insect by chance escape the murderous jaws of its enemy, the latter immediately commences throwing up the sand, whereby, not only is the hole made deeper, and its sides steeper, but the escaping insect is probably hit, and again brought down to the bottom of the pit. It is chiefly upon ants and other soft bodied insects that these larvae feed. They are, however, capable of undergoing long fasts ; for one of my larvae remained from October till March without food. It has been supposed that, as the food of these larvae consists entirely of juices, and as they appear to be destitute of anal aperture, the whole of their food is assimilated. M. L. Dufour has,, however, traced the intestinal canal terminating in an anus, which is, indeed, very difficult to discover. ( Ann . Soc. Ent. de France, tom. ii. p. 67. app.) Latreille states that these larvae are produced in the summer or autumn, and become pupae in the following spring. I found the larvae of all sizes in July, one of which became a pupa, and assumed the perfect state ; whilst another, of equal size, re¬ mained through the winter in the larva state. Previous to assuming the pupa state, the larva forms a globular cocoon of less than half an inch in diameter (fig. 63. 17.) of fine sand, glued with silken threads spun from a slender telescopicdike spinneret, placed at the extremity of its body (fig. 63. 16.), and lined with fine silk. The pupa * ( fig. 63. 18.) is small, not being half an inch long, inactive, and with all the limbs laid at rest upon the breast. When ready to assume the perfect state, it uses its mandibles (fig. 63.19.), which are quite unlike those of the larva and imago, and which have not been before described f, to gnaw a hole through the cocoon, and pushes itself partly through the aper¬ ture, in which it leaves the pupa skin (fig. 63. 17.). Immediately on as¬ suming the perfect state, the abdomen is almost immediately extended to nearly three times its previous length, llbsel (Ins. Belust., t.iii. t.17 — 21.) ; Reaumur ( Memoires , tom. vi. pi. 32 — 34.) ; Percheron ( Guerin Mag.Zool ., p.59.); Disderi (in Turin Trans., tom. iii.) ; Bonnet ( Observ.
* Mr. Guilding observes of Formicaleo (a genus separated by Leach from Myr- meleon), “ Nympha dum nocte declaratur, acetabulum elongatum emittens,” and in a subsequent page he seems to regard the acetabulum as analogous to the meconium of many animals, noticing also its chemical composition. Reaumur has also noticed it. (Mem,., tom. vi. p. 372.)
j- Reaumur states that it is after the insect has become an imago that it gnaws a hole through the cocoon and escapes ; but, as the pupa skin is found half protruded through the orifice, it is clear that it is whilst a pupa that this opening is made : indeed, this is the only use the pupa has for its mandibles.
NEUROPTERA.
MYRMELEONIDJE.
45
diverses sur les Ins., tom. ii.), have given numerous details, and f ntev- esting accounts of the habits and structure of this larva.
Bonnet discovered, in the environs of Geneva, specimens of a larva which differed from the common one, in not crawling backwards, but forwards, with the head raised, and in not forming a pitfall ; the body is considerably longer, and more pointed, and the hind legs affixed so as not to be so completely concealed beneath the body. ( Bonnet , op. cit. p. 282.; and Reaumur , tom. vi. p. 377.) Latreille thinks it probable that this larva belonged to a species of Ascalaphus, rather than to Myrmeleon ; but, from the account given by Mr. Guilding of the preparatory states of the former of those genera, this is evidently not the case. It appears rather to be the larva of M. Libelluloides, or an allied species, agreeing in some respects with the larva of that insect described by Ionicus in the Entomol. Magazine, vol. iii. p. 461., and which he states generally feeds upon heteromerous beetles, lurking underground in the sand, without making a pit.
M. Percheron has figured a larva with details, which he gives as that of M. Libelluloides, but it does not accord with the description of Ioni¬ cus. Guilding’s account of the economy of a species allied to M. Libelluloides (the type of Leach’s subgenus Formicaleo), does not materially differ from that of M. formicarium.
The genus Ascalaphus Fair, is remaikable for the peculiar struc¬ ture of its antennae, which are very long and knobbed, like those of a butterfly [fig. 63. 21.), whence Scopoli and others described one of these insects as a Papilio. Mr. Guilding states that his species A, MacLeay- anus sits quietly during the day upon dry twigs, and with its abdomen at an angle so as to resemble a twig, and thus deceive its enemies. The eggs, from sixty-four to seventy-five in number, are deposited at the extremity of the twigs in a double row, and defended from their enemies by “circulis multis repagulorum.” These repagula are con¬ sidered to be without analogies in the animal creation ; they are “ elongata, pedunculata, subdiaphana, rufescentia;” they are expelled from the ovary by the female with as much care as though they were real eggs, and are so placed that nothing can approach the brood ; nor can the young ramble abroad till they have acquired strength to resist the ants and other insect enemies. The abdomen of the larva is de¬ pressed and oval, with ten pectinations on each side ; all the legs are gressorial — “ Larva segnis, corpus pectinesque arenulis tegens, man- dibulisque sub lateribus reconditis prcedam expectans.” (Linn. Trans.,
46
MODERN CLASSIFICATION OF INSECTS.
vol. xv. p. 511.) The figures which L. Guilding sent to the Linnaean Society, in illustration ol' the history of this curious insect, were not published. I am able, however, to give a figure (63. 20.) of a larva contained in the collection of the Rev. F. W. Hope, which is evidently that of an Ascalaphus. The head is very flat, deeply emarginate be¬ hind, and the sides of the body are furnished with twelve setose ap¬ pendages on each side.
The family Hemerobiidte * (Hemerobidae Leacli ) is composed of insects nearly allied to the preceding, but having a shorter and more delicate body, broader wings, and long filiform and multiarticulate antennae (Jig. 64. l. Chrysopa perla). The head is small; the eyes prominent, rounded {Jig. 64. 2.), and often splendid golden-coloured
Fig. 64.
number) in Osmylus ; the mouth is powerfully organised ; the upper lip large, and rounded at the anterior angles; the jaws {Jig. 64. 3.) horny and acute, with a tooth below the centre ; the maxillae {Jig. 64. 4.) long, with the inner lobe broad and ciliated, and with a broad, compressed, hirsute external lobe ; the lower lip {Jig. 64. 5.) is entire and rounded, arising from a distinct leathery mentum ; the prothorax
* Bibeiogr. Refer, to the Hemerobiide..
Leach. Zool. Miscell., vol. i. p. 45. (Nymphes.)
Newman, in Ent. Mag. No. 22. (Ithone ) — Ditto, No. 24. ( Drepanepteryx, new species, &c.)
Bowerbank. Circulation in Wing of Hetnerobius, Ent. Mag. No. 17.
Griffith. An. Kingdom Ins., pi. 72.
Savigny (Egypt), Curtis, Stephens, Fdbricius.
NEUROPTERA. - IIEMEROBIID 2E.
47
forms a distinct piece, narrower than the head and meso-thorax ; the abdomen is of moderate length, curved, and not furnished with ter¬ minal filaments ; the wings large, deflexed at the sides of the body during rest, and much reticulated ; the posterior being rather smaller than the anterior, and not folded ; the legs are simple and slender, with 5-jointed tarsi, terminated by two claws and a pulvillus ( Jig. 6^.6 J.
These insects are of a small, or but moderate size, and appear to be chiefly inhabitants of temperate climes. The exceeding brilliancy of the eyes of some species, resembling polished gold, and the very delicate structure of the wings, which reflect the prismatic colours, are especially worthy of notice. They emit, however, a very disagreeable odour when handled: they fly generally during the twilight, remaining inactive during the day. In their motions they are very sluggish.
The females deposit their eggs upon plants, attaching them at the extremity of a long slender and stiff footstalk, of a white colour, the base of which is fastened to the leaf (Jig* 64. 7.). This filament is composed of a viscid matter, discharged by the female at the time of laying her egg, which very quickly hardens on exposure to the air. In this manner they are fixed in small clusters, and have all the ap¬ pearance of minute fungi. It has been suggested that it is for the purpose of protecting them from the attacks of parasites that this pro¬ ceeding is adopted. The larvae hatched from these eggs are very voracious, feeding upon Aphides ; and thus, in conjunction with the larvae of the Coccinellidae and Syrphidae, they are very serviceable to the agriculturist. Unlike the ant lion, these aphis-lions, as Reaumur has termed them, are wanderers, seeking their prey where it is to be found in the greatest abundance. The body ( Jig . 64. 8.) is long and depressed, with the segments very distinct, and gradually narrowed to the extremity of the body ; the head of moderate size, and armed with long curved mandibles, wherewith the insect seizes and sucks its prey. No description of the mouth of these larvae has hitherto been given, Reaumur merely stating that the mandibles are hollow, for suction. Such is not, however, the case ; the under side of these organs is deeply grooved, and the maxillae, which are nearly equal to them in size, and of a similar form, play in this groove ; there are no maxillary palpi; — the labial palpi are long, porrected, and apparently 3-jointed ; the antennae are also long and filiform, but I cannot clearly perceive any articulations [Jig 64.9. under side of front of head of larva). So ravenous are these larvae that it does not require more than half a minute for them to suck one of the largest Aphides. They will
48
MODERN CLASSIFICATION OF INSECTS.
also attack each other, the conqueror in like manner sucking the body of the vanquished. The head is capable of very considerable movements, owing to the flexibility of the neck. During the summer, it does not require more than fifteen days for them to arrive at their full growth. They assume the pupa state immediately after finishing their cocoon, in which they remain, as inactive pupae, during the winter. M. Audouin has informed me that the manner in which the imago makes its escape from its cocoon is not by a head-piece scaling off, but by a slit at one end of the cocoon being continued in a spiral direction, forming a nar¬ rowed and elastic slip. See also Reaumur {loc.cit.) ; Sowerby ( British Miscellany , pi. 66. larva of Hemerobius — ?); Haworth, in Ent. Trans ., p. 62. ; Disderi (in Turin Trans ., vol. iii.) ; Albin (pi. 64.) ; Goedart (No. 104.) ; De Geer (in Der Naturforscher , tom. iii. t. 3.).
The perfect insect of Chrysopa perla has afforded to Mr. Bowerbank the subject of a valuable paper on the circulation of the blood of insects ( Entomol . May., vol. iv. p. 178. ; and see Tyrrell in Proceedings of Royal Society').
M. Rambur has shown me specimens of two species of a new genus of this family, captured by him in Andalusia, in which the antennae are strongly bipectinated.
Reaumur ( Mem., tom. iii. pi. 32, 33.) has represented four different kinds of larvae belonging to this family ; but, unfortunately, it is im¬ possible to ascertain what are the species to which they respect¬ ively belong, with the exception of one, which is evidently that of Chrysopa perla. In one of these larvae the sides of the segments are furnished with short bundles of hairs *, of which the others are destitute. One of these is naked, and of an elongated depressed form (like fig. 64. 8.) ; whilst another is equally naked, but much more convex, employing the extremity of the body as a seventh leg, and having the segments more continuous. The larva of Chrysopa perla is also convex, but it covers itself with the carcasses of its victims, which gives it a most ludicrous appearance, and at the same time renders it almost invisible amongst lichens, &c. When full-fed these larvee inclose themselves in globular or oval cocoons of silk, spun from the spinneret, at the extremity of the body, and which in some species are exactly like open network. Compared with the perfect, insect, the small size of the cocoon and pupa appears extraordinary,
* Frisch represents the larva of C. perla as furnished with fascicles (vol. i. st. 3. fig. 23.).
NEUROPTERA. - HEMEROBIID^E.
49
the cocoon not being larger than a small pea, whilst the imago is nearly an inch long.
F. Stein has described the pupa state of Osmylus maculatus (the largest British species of the family), which is found in damp earth in the banks of ditches ; when preparing to undergo its final trans¬ formation, it quits its abode, and creeps up the stems of grass. (Weigman’s Arch., vol. iv. p. 332.).
A singular genus of minute species, which I first described under the name of Coniortes (fig* 65. l. C. tineiformis), ( Proceed . Trails. Ent. Soc., July 1834; subsequently figured by Curtis under the name of Coniopteryx, Brit. Ent., 528. December, 1834, and by Wesmael under that of Malacomyza), appears to me, although placed by Curtis and Stephens in the family Psocidse, to belong to the Hemerobiidae, with which it agrees in its head (fig. 65.2.); 5-jointed tarsi (fig. 65. 7.) ; multi-articulate antennae ; labrum (fig. 65. 3.); mandibles (fig. 65.4.); and maxillae (fig. 65. 5.). It differs, however, in the slight reticulation of the wings ; their white mealy covering (exhibiting no appearance of ciliae, hair, or scales); the large size of the terminal joint of the labial palpi; the obsolete labium (ligula) (fig. 65. 6.); the absence of tibial spurs ; and the smaller size of the posterior wings. The species sit with the wings deflexed, and feign death by bending their antennae under the body. Mr. Curtis has figured a singular larva (fig. 65. 8.) belonging to this genus, communicated by Mr. Haliday, who thinks it is probably aphidivorous, and enter¬ tains no doubt that it is the larva of C. tineiformis. He says its general character is closely allied to the larva of Hemerobius, but the structure of the head appears to me to be very different. The fol¬ lowing note has been since kindly communicated to me by the latter gentleman. “ Coniopteryx tineiformis, when preparing for trans¬ formation, spins an orbicular pouch of fine white silk of close texture generally on the trunk of a tree, in chinks of the bark, or among moss. The pupa is quiescent (fig. 70. l.) ”
The family Sialidve * Leach consists of a few species of moderate or large size (fig. 64. 10. — 22. Sialis lutaria, and details), constituting
* Bibliogr. Refer, to the Sialid.e. Suchow , in Zeitschr. fur die Organ. Rhys., tom. ii. No. 3. Pictet , in Ann. Sci. Nat., second series, tom. v.
VOL. II.
E
50
MODERN CLASSIFICATION OF INSECTS.
the tribe Megaloptera (Latr., Nouv. Diet, d' Hist. Nat. Tabl. Meth.). They are distinguished by the larger size of the quadrate prothorax ; the palpi are short and filiform, the last joint not being larger than the preceding ; the head of moderate size {fig. 64. ll.) ; the labrum is cleft in the centre {fig- 64. 12.); the jaws horny, with a single sharp apical tooth (Jig. 64. 13.) ; the maxillae are terminated by two minute lobes; the maxillary palpi in Sialis are 4-jointed (Jig- 6 4. 14.) ; the labium is large, with reflexed 3-jointed labial palpi, the true labium (ligula) not extending beyond the palpi, but internally dilated (Jig. 64.15.) ; the anterior wings are of large size, either deflexed at the sides (Sialis), or carried nearly horizontally (Corydalis, &c.), the posterior pair are rather smaller than the anterior ; the antennae are long, fili¬ form, and multi-articulate ; and the tarsi are 5-jointed, either with the joints simple, or with the fourth joint lobed beneath (Sialis, fig. 64. 16.) The ocelli are absent in Sialis, but they exist of a large size in Corydalis.
These insects are very slow and inactive in their movements ; they frequent the neighbourhood of water, in which they pass the larva state. The ordinary species (Sialis lutaria Linn.), is a well- known bait with the angler, being produced in the spring months in great quantities. It is of a dull brown colour, and may be found upon walls or palings near the water. The female deposits an immense quantity of eggs, which she attaches one by one to rushes or other aquatic plants ; they are of a cylindrical form, terminating at the top in a sudden point ; they are attached together side by side with the greatest regularity (Jig. 6^. 17.). The larva (Jig. 64. 18.) inhabits the water, in which it swims well by the assistance of seven (Latreille, De Geer, and my specimens, or eight, according to Pictet) pairs of slender 4- (5- ?) articulated setose filaments, attached at the sides of the abdominal segments, representing the false gills of the larvae of Ephemeridae, with which they are evidently analogous in their respir¬ atory action.* * The abdomen is terminated by a long and slender
Gray, in Griffith An. Kingd., pi. 72.
De Geer. Memoires, tom. iii. tab. 27.
Palisot Beauvois. Neuropt., pi. 1.
Drury. Exotic Entomology, vol. i. pi. 46.
Newman. Entomol. Mag., No. 25.
* M. Pictet notices the curious fact, that one of these larva? lived fifteen days in the earth before it changed to a pupa, being the only instance of an insect furnished with external respiratory organs respiring the ordinary atmospheric air.
NEUROPTERA.
SI ALIDiE.
51
setose tail ; the legs are of moderate length, and terminated by two claws ; the head is scaly, and furnished with eyes and antennae. The mouth of the larva consists of an angular upper lip ; a pair of strong mandibles, armed with two teeth at the middle of the inner margin (jig* 64. 19.); the maxillae are curved, and furnished with a kind of bifid palpus, according to Pictet ; but more properly consisting of two lobes, the inner acute, curved, and armed with three strong spines ; the outer lobe has its inner angle produced into a point ; the maxillary palpus consisting of four joints ( fig . 64. 20.) ; the labium, with its short 3-jointed palpi are represented in jig. 64. 21. ; the above figures being the first which have yet been published of the details of the curious mouth of this insect either in the larva or perfect state. The antennae are setaceous, and 4-articulated ; the three thoracic seg¬ ments are of nearly equal size; the tenth abdominal lobe constitutes the setose tail. When full grown, this larva quits the water, and bur¬ rows into the adjoining bank, in which it forms a cell, wherein it is transformed into an inactive pupa (jig. 64. 22.), with the limbs laid along the breast ; it is, however, very lively, twisting its tail about when disturbed. The insect assumes its perfect form in its cell (De Geer, Memoires , tom. ii. p. 716.; Rbsel, Ins., tom. ii. class 2.; Ins. Aq., tab. 13. ; Pictet and Suckow, loc. cit. supra ; Frisch, tom. i. pt. 8. tab. 14.).
The family comprises two distinct subfamilies: — 1st, the Sialides, described above ; and 2d, the Corydalides, having the tarsi simple, three ocelli, and the wings carried nearly horizontally when at rest. The latter insects appear to form a link between Hemerobius and Perla. Latreille considers Corydalis as allied to Raphidia (Gen. Cr., tom. iii. p. 199.). They are of large size, and often handsomely varie¬ gated ; they are chiefly, if not exclusively, inhabitants of North America. The largest of these (Corydalis cornuta Latr.) is distin¬ guished by the immense size of the mandibles in one sex. De Geer’s figure 2. pi. 27. tom. iii., evidently represents the head of the female. Chauliodes is distinguished by the strongly pectinated antenna?. There are several other undescribed genera belonging to this section, to which also belongs a species figured in Griffith’s An. Kingd. Ins., pi. 72., under the name of Chauliodes maculipennis G. R. Gray ; but previously described by Say.
52
MODERN CLASSIFICATION OF INSECTS.
The family Panorpidje* Leacli is at once distinguished by the front of the head being produced into an elongated slender deflexed rostrum
Fig. 65.
(Jig. 65. 10. 11.), at the extremity of which the parts of the mouth are inserted. The body is moderately long and slender (fig. 65. 9. Panorpa communis $ ) ; the head isVertical, and not broader than the front of the thorax; the eyes prominent and semiglobose (fig. 65. 10.) ; the antennae long, slender, and multi-articulate ; the clypeus is acuminated at the tip, leaving the sides of the leathery ciliated labrum exposed ( fig. 65. 12.) ; the mandibles are very small, narrow, toothed at the tip (fig. 65. 13.) ; the lower jaws and lower lip are elongated, the basal parts of the former being soldered together, so as to form the under side of the rostrum (fig. 65. n.) ; the maxillae are bilobed at the extremity ( fig. 65. 14.), membranous, and pilose ; the maxillary palpi 5-jointed ; the lower lip is inserted upon the united base of the maxillae (fig. 65. ll .), it is narrowed in front, and does not extend beyond the base of the labial palpi, which have been described as only 2 or 3-jointed. I have represented them, in fig. 65. 15., as they ap¬ pear under a strong lens, in a dried specimen. The prothorax forms
* Bibliogr. Refer, to the Panorpidas.
Linnaeus, in Trans. Holm. 1747. s. 176.
Sivederus, in Trans. Holm. 1787.
Westwood, in Trans. Ent. Soc., vol. i. p. 75. app. (3 sp. of Nemoptera. )
King. Monograph. PanorpicUe, in Trans. Acad. Berlin, 1836. (See Ann. Soc. Ent.
France, 1836, p. 75. app.)
Newman, in Ent. Mag., No. 22. (Merope. )
Pictet, in Mem. Soc. d’ Hist. Nat. Geneve, tom. vii. p. 403.
Hardwick, in Linn. Trans., vol. xiv. ( Panorpa furcata. )
Stephens, Curtis, Fabricius, Thunberg (2 sp. Panorpa.)
NEUROPTERA. - PANORPIDiE.
53
a very short narrow collar ; the mesothorax is large ; the wings are of moderate and equal size, numerously reticulated, the posterior not being folded when at rest. The legs are long and slender ; the tarsi 5-jointed, simple, with two tibial spurs, and denticulated ungues, and a large pulvillus ( Jig. 65. 16.).
The type of this family is the Panorpa communis Linn., from which the leading characters given above are chiefly drawn. It is a very abun¬ dant species, known under the ordinary name of the scorpion-fly, from the singular apparatus with which the extremity of the body of the males {Jig- 65. 9.) is armed. In this sex the sixth and seventh abdominal segments are slender, and somewhat recurved ; and the eighth segment is greatly thickened, forming an oval mass, armed with a pair of for¬ ceps. In the female the terminal segments are attenuated, and fur¬ nished at the tip with a pair of very minute 3-jointed filaments (Jig. 65. 17.), These insects, as far as hitherto observed, feed upon other insects in the perfect state. They are very active, and the elon¬ gated abdomen is capable of great motion in every direction, as well as considerable elongation, evidently enabling the female to deposit her eggs in deep holes or crevices. They are generally found in hedges, and amongst herbage, in damp situations. Of the larva state of these insects, no observation has been hitherto recorded. M. Macquart gave a description of the pupa of the common species in the Annates Sci. Nat. 1831, tom.xxii. p. 463., without, however, being able to state any thing of its habits, or whether it was quiescent or active ; he thought it, however, most probable to be active, because it was provided with limbs proper for motion ; its structure, however, clearly showed it not to be aquatic in this state. F. Stein has, more¬ over, published a figure of the pupa (Jig. 65. 18.) of the female (as is evident from the structure of the abdomen, although he calls it the male) of P. communis, which he found at the depth of an inch in moist earth, at the foot of an alder stump. From this figure it is evi¬ dent that it is inactive in this state, the limbs being laid along the breast, and the antennae along the sides ; the head is much less elongated than in the imago ( Jig. 65. 19.) (Wiegmann’s Arch., vol. iv. 331.).
The other English genus Boreus Latr. (Ateleptera Hojf mans'), forming the family Boreidae StejAt. and the osculant order llaphioptera MacL. (Horce Ent., 439.), comprises a single species of minute size and singular structure, agreeing with Panorpa in the general structure
e 3
MODERN CLASSIFICATION OF INSECTS.
54
of the mouth, but remarkably differing in the apterous condition of the female, and the style-like form of the wings of the male. The abdomen of the female is terminated by a 3-jointed ovipositor, the under side of which is defended by a produced valve-like bilobed plate, arising from the under side of the seventh segment ( Jig. 65. 22.), The male (frontispiece, vol. i. Jig. 3.), has the abdomen (Jg.65. 20.) terminated by two short, recurved, attenuated, pilose styles ( fig . 65. 21.). The antenna; are 23-jointed. This genus differs from all the others in the family by the large size of the prothorax, and the want of ocelli. The period for the appearance of these insects in the per¬ fect state is in the middle of winter. Dalman observes that those found in autumn in moss are pale-coloured and immature, and that the dark-coloured mature ones are to be found on the surface of snow. Stephens states that it has been found in England under moss and stones, at the same period.
The exotic genus Bittacus Lcitr., in the structure of its mouth and thorax, and possession of ocelli, is closely allied to Panorpa ; but its general appearance is that of a large Tipula, resulting from the great length of the legs and wings, which are carried horizontally in repose. The abdomen is alike in both sexes, and the tarsi are terminated by a single unguis. Dr. Klug describes eleven species of this curious and widely distributed genus.
The genus Merope Newm. ( Ent . Mag., No. 22.), from North Ame¬ rica, is certainly referrible to this family ; agreeing with Panorpa in the essential structure of the mouth ; but the ocelli are wanting ; the eyes reniform ; the antennae thickened in the middle ; and the protho¬ rax enlarged. The specimen described by Mr. Newman is a female, and has the abdomen terminated as in the female Panorpa ; the in¬ ternal base of the fore wings is furnished with a small incrassated lobe.
Nemoptera Latr. comprises some of the most singularly formed species in the order, peculiar to Africa and Western Asia, Portugal, &c., having the wings extended when at rest, the posterior pair being several times longer than the entire body, and linear ; the ocelli are wanting; and the structure of the mouth (represented in detail in the great work on Egypt) is very different from that of Panorpa, approach¬ ing much nearer in the articulation of the maxillae and developed ligula, to the Hemerobiidae ; indeed, Dr. Klug has removed it from this family in his monograph. Olivier, who observed them in the Levant, states that their flight is slow and heavy, so that they are
NEUROPTERA. - RAPHIDIIDZE,
caught without difficulty. They appear in great numbers, and live but a very short time. The Rev. F. W. Hope possesses a singular monstrosity occurring in a specimen of N. coa, in which one of the anterior wings is partially undeveloped.*
It is in this place that I may notice a singular insect, figured by P. Roux in the Annales Sci. Nat., tom. xxviii. pi. ?., under the name of Necrophilus arenarius (fig. 66. l.) ; but which appears to me to be a Neuropterous larva, exhibiting considerable affinity with the larvae of the Hemerobiidae. If the relation of the Nemopterae with that family be proved, is it possible that this may be the larva of that genus? The body is oval, with a slender linear neck, longer than the entire body ; small head ; long sickle-shaped mandibles ; two an¬ tennae, and six long simple legs. From its size it might either pro¬ duce a Nemoptera, Bittacus, or Panorpa.
The family Raphidiid.® f Leach, consisting of the single genus Raphidia Lin., is a singular little group, distinguished by the elongated neck-like prothorax, flattened head, and simple forelegs as well as by the elongated ovipositor of the female {fig- 66. 2. Raphidia ophiopsis $ ). The head {fig. 66. 3. under side of head) is oval and flattened, broader than the prothorax, with prominent eyes placed at the front of the sides of the head ; the ocelli, three in number (but wanting in R. crassicor- nis), are placed between the eyes ; the antennae are slender, filiform, and
* See for descriptions of species Olivier, Encycl. Meth. ; Leach, in Zool. Misc., vol. ii. ; Ahrens, Fauna, fasc. 2. ; Savigny, Descr. de VEgypte ; Klug, Monogr. Panorp. (12 species); Westwood, in Trans. Ent. Soc., vol. i. p. 75. App.
f Bibliogr. Refer, to the Raphidiidh*:.
Latreille. Obs. Raphidia Ophiopsis (with fig. of larva), Bull. Soc. Phil. 1798. No. 20. A. 7. p. 153.
Schummel. Versuch ein gen. beschreib. — der gattung Raphidia. Breslau, 1 832, 1 pi. 8vo. pp. 16.
Percheron, in Guerin’s Mag. Zool. Ins., pi. 66.
Waterhouse, in Trans. Ent. Soc. London, vol. i.
Stein, in Weigmann’s Archiv. fur Naturg., tom. iv. pi. 7.
Stephens, Curtis, Schaffer, Panzer, lUiger ( Rossi Faun. Etrusc. ).
E 4e
56
MODERN CLASSIFICATION OF INSECTS.
Fig. 66.
multi-articulate ; the labrum small and quadrate, arising from a distinct leathery clypeus ; the mandibles powerful, curved, and strongly toothed [fig. 66. 3.) ; the maxillae are terminated by two lobes strongly pilose; the palpi short, filiform, and 5-jointed, the basal joint being very mi¬ nute ; the labium small, with short palpi, of which the terminal joint is longest; the hind part of the head is constricted into a neck or rotula, playing in the anterior aperture of the singular cylindrical prothorax, which is long and narrow, the sides being deflexed, and meeting in the middle beneath, so that one folds partially over the other {fig. 66. 4.) ; the meso- and meta-thorax are much broader, and of equal size ; the legs are slender and simple ; the anterior pair are inserted at the under side of the prothorax, where its deflexed angles, being cut off, leave a triangular space in front of the meso- sternum (fig. 66. 4.) ; the tarsi (fig. 66. 5.) are 5-jointed, the third joint being deeply bilobed, and the fourth joint small, and affixed between the lobes of the preceding. Percheron describes the ungues as composed of two pieces, of which the apical one is moveable ; but this is certainly incorrect. The abdomen is sessile, of moderate length, 9-jointed, and terminated in the females by a long sabre-like ovipositor (fig. 66. 6.) of a slender construction, composed of two plates (De Geer, Mem., tom. iii. pi. 15. f. 9.) very much compressed, transversely striated, longitudinally ribbed, and terminated by two minute oval appendages (fig. 66. 7.) ; the wings are moderately large, of nearly equal size, the posterior not folded when at rest, when they are deflexed at the sides of the body : they are strongly veined, the veins being inconstant, even in the same individual ; but their general arrangement is as in the Sialidm, &c., with a distinct stigma,
NEUROPTERA. - RAPIIIDIIDiE.
57
of which the differences of form have been employed as specific characters.
These insects are of comparatively small size, agile in their move¬ ments ; the astructure of the head and neck, powerful jaws, and the elongated coxae of the legs, as well as the membranous attachment of the segments of the body, indicating predaceous habits. They receive their English name of snake-flies from the form of the head and neck, and the facility with which they move the front of the body in dif¬ ferent directions. It is in the neighbourhood of woods and streams that these insects are chiefly found.
This family seems to occupy an intermediate situation between the larger species of the Sialidae and the Mantispidae, agreeing with the former in the enlarged size of the prothorax and structure of the head, and with the latter in general form.
The transformations of these insects have formed the subject of memoirs by Latreille, Percheron, Waterhouse, and Stein.
The larva, for a specimen of which I am indebted to Mr. Ingpen, resides (according to Percheron, who reared two species) under the bark of trees ; it is predaceous, and feeds upon minute insects * ; it creeps but slowly, but gives to its body violent jerking motions in every direction, somewhat like those of a serpent. It is long and narrow ( Jig . 66.8.), with the abdominal part of the body pubescent, dilated in the middle, and not so scaly as the head and prothorax ; it is 13-jointed including the head, which is oblong, flattened, with short 3-jointed antennae, not including the radicle (Jig. 66. 12.); the jaws are robust, curved, acute at the tip, with a strong tooth on the inner margin {Jig. 66. 9.) ; the maxillae (Jig. 66. 10.) and labium are distinct (Jig. 66. 11.), with short palpi ; the legs are short (Jig. 66. 14. tarsus) ; the abdomen is unarmed ; the eyes resemble ocelli (Jig. 66. 13.), and are situated near the base of the antennae. I cannot observe more than two on each side of the head, which is the number also noticed by Waterhouse ; Percheron, however, states that there are seven on each side. The pupa is not inclosed in a cocoon. It resembles the perfect insect in general form, but is furnished only with short rudi¬ ments of wings, lying at the sides of the body (Jig- 66. 17. male pupa,
* Mr. Waterhouse states that he always found the larva? in the bark, in which they formed cells for themselves, and that he never observed them to feed upon other insects, although he admits that the structure of the mouth is that of a predaceous rather than a lignivorous insect. I should apprehend that the larvae noticed by Mr. Waterhouse were preparing a retreat for their pupation.
58
MODERN CLASSIFICATION OF INSECTS.
from Waterhouse, fig. 66. 15. female pupa, fig. 66. 16. extremity of its abdomen sideways). Linnaeus was acquainted with the pupa, which he thus describes : “Pupa currit, matri simillima, licet aptera. Caput ob- cordatum." (Syst. Nat., tom. ii. p. 916.) Percheron denies that the pupa possesses this active power, and asserts that the entire body of the pupa merely “ jouit de la meme faculte de contorsion et de sauts, que la larve execute a un si haut degre.” Mr. Waterhouse has (quite correctly as it appears to me from analogy with some other quiescent pupae, as Myrmeleon, & c.) reconciled these statements by observing that the pupa in some respects approaches the active pupae, although it cannot be strictly considered as such until immediately before as¬ suming the imago state, when the insect having gained sufficient strength, is enabled to walk, although inclosed within the pupa skin, which, by the bye, is extremely thin. A peculiarity existing in this pupa, which has not been alluded to by previous writers, clearly proves it to be inactive in the early stage of the pupa state, namely, that the hind legs are partially covered by the wings. (Compare Jig 66. 15. with Jig. 41. ll. p. 336., or fig. 48. 19. p. 387.) The species are very few in number, and I am not aware that any have been discovered out of Europe.
The family Mantispidje * Westw., like the preceding, consists of a single anomalous genus, whose situation has greatly perplexed sys- tematists, none of whom, however, appear to have given themselves the trouble of investigating the structure of its mouth.-j' As already noticed, in vol. i. p. 412. note, it is without hesitation that I regard this genus as
* Bibliogr. Refer, to the MANTisPiniE.
Stoll. Representation des Spectres, &c.
Serville and St. Fargcau. Encycl. Meth., tom. x. p. 270. Latreille. Genera Crust., vol. iii. p. 94.
Newman, in Entomol. Mag., No. 24.
Charpentier. (Horie Entomol.)
Guerin, (Voy. Coquille. )
f I must now omit my friend Erichson, who (in his admirable monograph in Dr. Germar’s Zeitschrift fiir die Entomologie, No. 1. 1839, just received by me from the author) has investigated the affinities of the genus, and arrived at the same conclusion as myself. He describes twenty-four species chiefly from Africa and America, but I am acquainted with several others yet undescribed.
NEUROPTERA. - MANTISPIDiE.
59
the type of distinct Neuropterous family, very closely allied to Heme- robius, both in the trophi and in the general character of the veins of the wings. The body is long and narrow {Jig. 66. 18. Mantispa pa- gana), somewhat like that of Raphidia, with a broad head, large pro¬ minent eyes, short submoniliform antennae, and an elongated prothorax, narrower than the head, but dilated in front : the ocelli are wanting, the clypeus and labrum distinct ; the palpi short and filiform {Jig. 66. 19. front of the head) ; the mandibles are horny and acute, but slightly curved, and occasionally with a small tooth within (Jig. 66. 20.) ; the maxillae are long and bilobed : the outer lobe broadest at the tip, where it is subarticulated and pilose ; the maxillary palpi are 5-jointed, the terminal joint being longest (Jig. 66. 21.) ; the labium is oblong, extending considerably beyond the insertion of the palpi, and entire at the tips (Jig. 66. 22.) ; the prothorax is greatly elon¬ gated, and formed upon the plan of that of the Mantidae, but it is not margined ; the fore legs are attached on the under side close to the head (Jig. 66. 23.), they are raptorial, like those of the Man¬ tidae ; the other legs are simple ; the tarsi 5-jointed, with denticulated ungues ; the wings are of nearly equal size, deflexed at the sides of the body in repose, and numerously veined ; the veins being arranged somewhat as in the Hemerobiidae ; the abdomen is not furnished with terminal filaments, or an exserted ovipositor.
The structure of the fore legs and mouth of these insects warrants the conjecture that they are predaceous in their habits. Latreille informs us that they reside upon oaks, their habits, and probably their metamorphoses, being identical with those of Raphidia. M. Bourgeois, who frequently captured M. pagana in the neighbourhood of Lyons, communicated a larva to Latreille, constructed like that of Raphidia, but considerably larger, and which, Latreille says, “je ne peux rap- porter qu’a cette Mantispe.” (Considerations Generates, p. 69.) I have in a preceding page noticed the use which has been made of these insects, with the view of establishing the passage between the Orthoptera and Neuroptera.
The species are but of moderate or small size, of dull colours, and widely dispersed, being inhabitants of Europe, South Africa, India, New Holland, Surinam, Brazil, &c.
60
MODERN CLASSIFICATION OF INSECTS.
Order TRICHOPTERA* Kirby.
(Elinguia Fetziiis, Neuroptera Plicipennes Latreille, Synistata p. Fabricius, Neuroftera p. Linn., Trichoptera p. MacL.')
Ciiar. Wings four, membranous ; the anterior generally pilose, with branching nerves ; the posterior larger, and folded when at rest. Prothorax very short.
Tibiae with long calcaria at the tip, and often beyond the middle of the limb in the four posterior legs.
Mouth unfitted for mastication ; mandibles rudimental.
Larva hexapod, ordinarily residing in a case formed of various materials, in which it retains its station by means of two hooked anal processes.
PujDa incomplete, inactive during the greater period of its exist¬ ence.
The insects of this order are the well-known caddice-flies, or water moths of the angler ; their larvae being called cads, or cad-bait, and residing in portable tubes, composed of various extraneous materials.
The body of the perfect insect (Jiff- 67. l. Phryganea grandis) is of a leathery consistence, and thickly clothed with hair; the head small ( fig. 67. 2, head of ditto in front), with prominent semiglobular eyes, and three f ocelli. The antennae are as long as, often much longer
*Bibliogr. Refer, to the Trichoptera.
Pictet. Recherclies pour servir a l’Hist. et a l’Anat. dcs Phryganides. Geneva, 1834. 4to. pp. 235, 20 pi. — Ditto, in Mem. Soc. Hist. Nat. Geneve, tom. vii. Stephens. Illustrations Brit. Ent., vol. vi.
Curtis. Brit. Entom., and in Londand Edinb. Phil. Mag., Feb. and March, 1834. Perch, eron. Genera des Insectes Olostomis [Holostomis phalaenoides nec daurica] Neur., pi. 3. (See Mannerheim (Rev. Critique, p. 21.) as to the specific synonyms of this genus).
Dolman. Mem. Acad. Stockholm, 1819. Analecta Entomol. (Hydroptila.) Fischer. Entom. de la Russie. 3 vols., 4to. Moscow.
Savigny. Description de l’Egypte.
Geoffroy, Linnccus , Schaffer, Scopoli, Gmelin, Villers, Olivier (Enc. Moth. tom. vi. ), Fabricius, Leach.
f M. Pictet states, “ On voit sur le front deux petits yeux lisses ” ( Recherch . Phryg.). This is true ; but there is a third ocellus between the base of the antennal in many species, forming, with the two on the forehead, a large triangle ; but Curtis describes the Limnepliili and Lcptoceri as having only two ocelli.
TRICHOPTERA. — PII RYGANEIDiE.
61
Fig. 67.
than, the body (as in Leptocerus (Mystacida) niger ,Jig. 67. 7.) slen¬ der, setaceous, and multi-articulate. The mouth is neither fitted for mastication nor suction ; it consists of an elongated, slender upper lip ( fig- 67. 3., after Savigny), at the base of which, on each side, ac¬ cording to Savigny {Mem. An. S. Vertebr ., pi. 1.), Curtis {Brit. Fnt., pi. 592.), and Percheron {Gen. Ins. Neur., pi. 3.), is to be perceived a minute, soft, pubescent, and trigonate organ {Jig. 67. 3. °°.), which is the representative of the mandibles (which are erroneously stated by Latreille and Pictet to be “ nulles ’’) ; the maxillae are also small, and terminated by an oval pubescent lobe {Jig. 67. 4.); the maxillary palpi are long and slender, being only 4-jointed* in the males of the large species {Jig. 67. 5.), but 5-join ted in the females {fig. 67. 4.). In the genus Phryganea, &c., the joints are of nearly equal thickness, and similar in their appearance; but in Hydropsyche {fig. 67. 8. maxillary, 67. 9. labial palpi), &c., the terminal joint is very greatly elongated, and much more slender than the preceding, and annu- lated ; and in the Mystacidae they are thickly clothed with hairs. The mentum is distinct and quadrate ; the labium produced and entire ; and the labial palpi 3-jointed {Jig. 67. 6. P. grandis), and partaking of the character of the maxillary palpi. The prothorax forms a very short collar. The meso- and meta-thorax are dilated into an oval or orbicular mass. The anterior wings are elongated and lanceolate in the females, but rather more obtuse in the males of the true Phry- ganeae ; they are deflexed at the sides of the body during repose, and
* Pictet describes them as only 3-jointed in the males of the true Phryganea;. Curtis and Percheron, however, figure them as 4-jointed. In the males of the other genera, they do not differ from the females in the number of joints. In the males of Sericostoma (Phryganea personata Spence, Introd. to Ent., vol. iii. p. 489., Sericostoma Spencii Steph . ), the maxillary palpi, in the males, are short and di¬ lated, uniting in front of the face, and forming an obtuse rounded mask ( fig . 67. 10.).
62
MODERN CLASSIFICATION OF INSECTS.
are furnished with numerous branching veins ; the costal portion is not transversely veined ; the posterior pair are shorter, but consider¬ ably broader than the anterior, and are folded when at rest. The wings are more or less clothed with hair (fig. 67* 11. fore wing of Hydro- ptila) ; the legs are long and slender ; the anterior tibiae are spurred at the tip, but the four posterior are furnished, not only with apical spurs, but also with one or two pair near the middle of the limb ; the coxae are also elongated — both which characters add materially to the acti¬ vity of the insects; the tarsi are 5-jointed, with minute claws and pul- villi. In the genera Hydropsyche Agapetus,&c., the intermediate tibiae and tarsi are dilated in the females ; this is also especially the case in an allied species figured by Savigny in the Description de lEgypte. The abdomen is of moderate length, slender, the extremity being fur¬ nished, in the males, with several short curved inarticulate appendages.
The females deposit their eggs in a double gelatinous mass, which is of a green colour, and is retained for a considerable time at the ex¬ tremity of the body ; the mass is subsequently attached to the surface of some aquatic plant, and Mr. Hyndman has observed the female of Phryganea grandis creep down the stems of aquatic plants under the water, very nearly a foot deep, for the purpose of oviposition ; on being disturbed, it swam vigorously beneath the water to some other plants ; its bundle of eggs was found to be of an oblong form, bent in the middle, and the two ends attached to the tail of the animal (Cur¬ tis, Brit. Ent., fol. 592.).
Fig. 68.
The larvae ordinarily reside in cylindrical cases, open at each end, to which they attach various matters, as bits of stick, weeds, pebbles, or even small living shells (fig. 68. 2. case of P. fusca Pictet ), by the assistance of silken threads, which they spin from the mouth in the
TRICHOPTERA. - PHRYGANEIDiE.
63
same manner as caterpillars. Some cases are formed of fine sand, and curved ( Jig. 68. 4. case of Sericostoma multiguttatum Pictet). The larva remains in this case, exposing only its head and three anterior segments of the body, and which it suddenly withdraws on the slightest alarm.
The cases formed by these larvae being ordinarily composed of mate¬ rials scarcely specifically heavier than the water, are easily carried about. There does not appear to be an exclusive regularity in the choice of the materials of which they are formed, according to the difference of species, the individuals of each employing, occasionally, what comes nearest to them when engaged in its construction. M. Pictet indeed appears to consider that each species chooses its own peculiar materials for the construction of its case, and that the mode in which these articles are applied is uniform. Thus, P. rhombica selects morsels of straws or twigs, which it arranges transversely (Jig. 63. i.); whilst P. lunaris employs the same materials, which it attaches longitudinally ( Jig. 68. 3.). He, however, mentions a variety of instances in which materials of a perfectly different kind had been employed by these species. In some species, the materials (ordinarily strips of leaves) are arranged in a spiral coil (Jig* 68. 9. pupa case of P. varia Piet. JReaum. 3. pi. 14. f. 9.).
When the case, owing to the growth of the inhabitant, becomes too small, it has been stated by some authors that the larva quits it and constructs a new one ; but M. Pictet considers that it rather adds fresh materials of an enlarged diameter at the aperture, cutting off a por¬ tion of the opposite end, which would account for the conical form which these cases often exhibit.
In the preface to the Historia Insectorum of Ray, p. xii., is pub¬ lished an interesting tabular arrangement of these cases, “ ex obser- vatione D. Willughby,” of which an extract will be sufficient to prove the assiduous but neglected researches of our celebrated countryman. “ Insecta aquatica thecis se contegentia sunt, vel theca immobili, seu lapidibus affixa, corpore vel subrotundato cum filamentis ad latera, piano et compressiore absque filamentis. mobili aut portatili, migratoria; Phryganea vulgo dicta. [Then follows an admirable description of the larvae inhabiting these moveable cases.] Suntque vel thecis rectis, vel habentibus festucas agglutinatas
GI<
MODERN CLASSIFICATION OF INSECTS.
parallelas [straw-worms]
transversas et breviores, quibus interdum admiscentur lapilli et conchulae ;
festucas nullas adhaerentes, sed lapillos aut arenulos quae vel teretes, [cod-baits] planae, seu compressae,
lapillis majusculis, thecae lateribus adhaerentibus nunquam supinae aut pronae parti ;
nullis ad latera adhaer. lapillis, sed theca utrinque in tenuem marginem, seu limbum procurrente velut alas quasdam, theca planiore et compressiore quam in superiore.
incurvis seu cornutis mavis dicere. Sunt enim horum thecae incurvae, et una extremitate majore, altera minore.”
The Rev. J. Morton, also, in his History of Northamptonshire , chap, vii., has entered into many particulars relative to these larvae and their cases, as has also Sir Humphrey Davy, in his Salmonia. See also Insect Architecture , chap. x. Isaac Walton has also given many particulars of these insects, especially as regards their piscatorial qualities, and which he calls cadis, pipers, cockspurs, straw-worms, or ruff-coats. In Mr. Ronald’s Flyfisher s Entomology various moderate¬ sized species of Phryganeae are termed sand-flies, grannums, and cin¬ namon-flies ; whilst one of the Mystacidae is naemd the silver horns.
The larvae of these insects {fig. 68. 10. larva of Phryganea rhombica Pictet) are of an elongated, nearly cylindrical form, with a scaly head {fig. 68. 11. upper, 68. 12. under side of head of larva of P. stri¬ ata Pictet ), furnished with a bilobed upper lip, a pair of strong man¬ dibles, obtuse at the tip, with several short teeth {fig. 68. 13. mand. of larva of P. striata Pictet), fitted for gnawing vegetable matters. In the larvae of Hydropsyche they are terminated by a more elongated tooth {fig. 68. 15. mand. of larva of H. senex Pictet) ; and these spe¬ cies are more essentially carnivorous than the others. The maxillae and labrum are small, fleshy, and soldered together {fig. 68. 14. P. striata Pictet) ; the former are terminated by two minute corneous points, supposed by Pictet to represent the terminal maxillary lobe and palpus, of which there is no other rudiment ; neither does there appear to be any labial palpi, except two exceedingly minute points on each side of the spinneret, which is also very minute. In the larvae of the Sericostomae and Rhyacophilae, the maxillary lobes are
TRICIIOPTERA. - PIIRYGANEFD7E.
65
more elongated ; and in the latter of these genera M. Pictet repre¬ sents the external lobe as articulated and palpiform. My Jig. 68. ig. represents the maxillae of the larva of Phryganea pellucida, after De Geer. The head exhibits no trace of antennae ; the corneous cover¬ ing of the eyes is very small, and apparently composed of points at the sides of the headland destitute of reticulations; the three tho¬ racic segments of the body are leathery, each being furnished with a pair of legs, the anterior pair of which are shorter and stronger than the others. In the larvae of the true Phryganeae there is a slender horn between the anterior legs, which Reaumur considered to be the spinneret, but the use of which has not been ascertained (Jig. 68. 17. prosternum of larva of P. striata Pictet). The nine abdominal seg¬ ments are more fleshy, being seldom exposed beyond the mouth of the case, in which they retain their station by means of three conical- fleshy tubercles on the first segment, and by the two moveable articu¬ lated appendages, of variable form, at the extremity of the body. In those species observed by M. Pictet, which reside in fixed cases, these abdominal tubercles are wanting, and the anal hooks are elon¬ gated, and placed upon long footstalks (Jig- 68. 18.), giving them great capacity for movement, and enabling them to fix themselves firmly in their rough and irregular retreats. Other peculiarities exist in the form of this organ in the different genera, which correspond with their various modes of life and movements. The abdominal segments are moreover furnished with white membranous filaments, of various forms, which are the external organs of respiration.
The food of the larva has been stated to consist of minute aquatic larvae, and such is the case with Ilydropsyche, M. Pictet having ob¬ served that the larvae prey upon those of other aquatic Neuroptera, and even upon each other, in a state of captivity ; but the greater number are purely herbivorous, the structure of their jaws being fitted for gnawing vegetable matters ; and M. Pictet supplied them with willow leaves, upon which they fed well ; the larger species devouring the whole leaf, but the smaller ones leaving the veins entire ; they would, however, occasionally attack other aquatic larvae.
From the common occurrence of these caddice worms, it is not sur¬ prising that they should have attracted the attention of the early na¬ turalists, by some of whom they were known under the names of Lignipcrdae ; and Reaumur and De Geer have entered very fully into their natural history and structure. The former of these authors
VOL. ir.
E
GO
MODERN CLASSIFICATION OF INSECTS.
( Memoires , tom. iii. Mem. 5.) lias described many of the varieties in the cases formed of leaves, twigs, straws, wood, stone, sand, or shells. He has also figured ( Ibid ., pi. 12, 13.) the transformations of P. striata (according to Linnaeus and Pictet), and, in pi. 14. f. 1 — 4., those of a species which Linnaeus quotes as P. grandis, but which ap¬ pears to agree both in the spirally-arranged case, and the spotted wings of the imago, with the P. varia ( Pictet , pi. 11. f. 1.). The cases of a minute species are also represented, together with the imago, in the same plate, but too vaguely to be determined ; they are probably a minute species of Mystacida ; whilst, in the fifteenth plate of the same volume, he has figured the cases of the larvae of a Mystacida Latr ., the hind legs of which are greatly elongated.
De Geer has entered more minutely than Reaumur into the details of the habits and structure of these insects, of which he traced five species through their different states. These are P. pellucida Oliv., Pictet (Mem., tom. ii. pi. 11, 12.), P. grandis (pi. 13. f. 1 — 17.), P. grisea (pi. 13. f. 18 — 21.), P. fusca ? (according to Goeze’s edit., vol. ii. p. 442.), and P. bimaculata Linn ., which is evidently a Mystacida. He, moreover, figured a variety of cases of different forms, of which he had observed the larvae, and of which some (pi. 15. f. 15 — 17.) are of a singular form, being apparently composed of fine sand, of an elongate-ovate shape, with a broad mouth and two protuberances at the opposite extremity. They probably belong to a species of Hydroptila. He, moreover, figured several perfect insects of which he had not observed the larvae.
Rosel ( Abhandl . von Ins., vol. ii., Ins. Aquat ., tab. 14 17.) has
figured various cases, together with the transformations of three species, which have been cited as P. grandis, striata, and rhombica.
With the exception of Reaumur’s figures in his fifteenth plate, above referred to, and those of De Geer’s of P. bimaculata (all of which are destitute of sufficient precision in the details), the various larvae figured by these authors are all referable to one type of form, having the head and three thoracic segments scaly, the legs mode¬ rately long, the basal segment of the abdomen furnished with three fleshy protuberances, and the third armed with two short hooks, with the external organs of respiration, consisting of slender soft filaments, arising separately, and lying transversely on the upper and under sides of the abdomen. Such are the characters of the larvse of the genus Phryganea, as restricted by Pictet. Those of
TRICIIOPTEltA.
PIIRYGANEID7E.
67
the genus Mystacida, as above noticed, differ in having the posterior pair of legs greatly elongated ; whilst those of Sericostoma have the external organs of respiration short and united on a common base, so as to form small bundles of short filaments. In the larvae of the Triclio- stomae the anterior angles of the thoracic segments are greatly pro¬ duced in front, forming acute points ; and in those of the Hydroptilae, the thoracic segments are narrow, and the abdomen swollen and destitute of external organs of respiration ; these reside in small flat¬ tened kidney-shaped cases, opened by a slit at each end (Jig. 68. 5. case of H. pulchricornis Pictet). M. Pictet further notices the interesting circumstance (long ago, however, observed by Willughby, as above detailed), that the larvae of many of these insects reside in immoveable cases attached to stones, &c., but formed of materials similar to the moveable cases* (Jig. 68. 6. case of Hydropsyche senex Pictet: Jig. 68. 8. elongated tortuous fixed cases, composed of silk and fine sand, formed by the larvae of Hydropsyche maculicornis Pictet). These larvae 'are therefore compelled to quit their retreats whilst searching for their food in a naked state, and they are accordingly better fitted for such a kind of life, by having the abdomen of a firmer consistence, with stronger anal hooks (Jig. 68. 18. larva of Hydro¬ psyche atomaria Pictet ), and the organs of respiration consisting of numerous short bundles (Jig. 68. 19. gills of the larva of Hydropsyche atomaria Pictet , Jig. 68. 20. gills of the larva of Rliyacophila vulgaris Pictet), or entirely wanting. Of these species the pupae of the genus Hydropsyche are enclosed in a single silky envelope, to which various materials are attached ; whilst those which have the pupa enclosed, in addition to this outer case, in another distinct internal cocoon (Jig. 68. 7. inner cocoon of Rliyacophila vulgaris Pictet) spun by the larva, com¬ pose the genus Rliyacophila of Pictet.
In those species which are destitute of external gills, the respiration is effected by spiracles placed on each side of each abdominal segment ; and species thus circumstanced are placed by Pictet in the same genus with others furnished with external organs of respiration.
From these considerations, M. Pictet has constructed the following
O
* M. V. Audouin communicated to the Entomological Society of France, on the 9th of January, 1833, a piece of granite, on the surface of which were a number of small rounded eminences, formed of minute granules of quartz, and which were dis¬ covered to be the cases of a small species of this family.
68
MODERN CLASSIFICATION OF INSECTS.
table, confirming, in respect to the peculiarities in the preparatory states, the genera founded upon the characters of the imago.
Larva? enclosed in a «( moveable case
with
a
circular
opening.
Thoracic segments <( rounded.
External organs of respiration isolated, legs moderate External organs of respiration in bundles.
Hind legs long - legs short
Larvae not enclosed in a move- able case.
Thoracic pointed ^opening with a slit
The pupa enclosed in f The pupa enclosed in
segments with
the front
angles
a double envelope a single envelope
}
Phryganea.
- Mystacida.
- Sericostoma.
Trichostoma.
- Hydroptila.
- Rhyacophila.
- Hydropsyche
M. V. Audouin has shown me the case of a small unknown species of this family, quite unlike any hitherto figured, being composed of fine sand cemented together, and saucer-shaped, so that it is difficult to conceive how the larva could employ it as a means of defence or abode.
When the period for assuming the pupa state is arrived, the larvae, which reside in moveable cases, fasten them to some fixed substance beneath the water, and close the two extremities with an openwork fence, which varies in form in the different species, and which, by admit¬ ting a current of water, permits the respiration of the pupa ; indeed, Reaumur states, that he actually saw this gratework in alternate motion from convex to concave, as the water passed out and in (fig. 67. 12. represents the grating of the case ofP. fusca? after De Geer). Within this retreat they then became inactive pupae, in which they bear a considerable resemblance to the imago, except that the an¬ tennae, palpi, wings, and legs are shorter, enclosed in separate sheaths, and arranged upon the breast (fig. 67. 13. pupa of P. pellucida De Geer), the antennae, in the species which have those organs, greatly exceeding the length of the body, being extended beyond the abdomen, with the extremities curled up ( fig. 67. 17. pupa of Mystacida bimacu- lata De Geer). The front of the head (fig. 67. 14. head of pupa of Hydropsyche senex Pictet) is moreover furnished with a pair of cor¬ neous hooks, but which are the real mandibles, crossing each other, and different in form from those of the larva and pupa, which give the head the appearance of a beak, varying in form and strength in the different groups, according to the nature of the cocoons (fig. 67. 15. mandible of pupa of Hydropsyche atomaria Pictet). With this the pupa makes its way through the openwork mouth of its case, shortly before assuming the perfect state, at which period it
TRICIIOPTERA.
phryganeid^e.
69
assumes considerable activity, swimming along, as I have observed, by means of its two hind legs, which are strongly ciliated, and crawling about by means of its four fore legs, which become detached from the breast. M. Pictet has made some interesting observations on the relations of the limbs of the pupa with those of the larva, and of the manner in which the former are enclosed within the larva skin. The pupae of the larger species creep out of the water, crawling up the stems of plants, &c., and undergoing their final change in the air ; but the smaller ones merely come to the surface, where they shed their pupa skin in the same manner as gnats, their old envelope serving them as a raft.
The pupa is furnished, as well as the larva, with external respiratory filaments, besides which, each of the segments of the abdomen, except the first and last {Jig. 67. 16. second abdominal segment of the pupa of P. striata Pictet), is dorsally provided with a pair of small patches, charged with recurved points, which evidently assist the pupa in making its escape from the case, previous to assuming the perfect state. The pupae of Phryganea have also a row of short filaments at the sides of the abdomen, the uses of which are unknown. The abdomen is also terminated by various appendages, of which the form varies in the different groups. The perfect insects are of small or moderate size, seldom reaching a couple of inches in the expanse of the wings. They are very active, running with agility with a kind of gliding motion, not unlike that of certain Tipulidae, and other insects with long tibial spurs ; but their flight is awkward, except in some of the smaller species, which assemble in troops, and fly over the surface of water towards sunset: they frequent damp marshy situations. From the weak structure of the mouth, it is evident that they can live but a very short time in the perfect state, taking no nourishment, and only anxious to continue their species. Their colours are obscure, being ordinarily brown or grey ; when handled, they emit a very disagreeable odour. A very few exotic species are ornamented with spots and markings. Few, only, have been brought from extra-European countries.
This order was first proposed by De Geer (to which his commen¬ tator Retzius applied the name of Elinguia), and included the Lin- naean Phryganeae and Ephemerae, which two groups were also united by Dumeril into his family Bucceles or Agnatlies. Linnaeus had united the Perlidae and Phryganeae into one genus, from the characters
f 3
70
MODERN CLASSIFICATION OF INSECTS.
of the imago, such as the folded wings, &c., which plan was also adopted by Lamarck. Mr. Kirby, in the 11th volume of the Linn. Trci?is., and subsequently Leach, restricted it to the genus Phryganea of De Geer, of which the leading characters are given above ; whilst Latreille retained the family as a distinct section of the order Neu- roptera, under the name of Plicipennes ; in this respect he has been followed by M. Pictet, who has substituted the name Phryganides. Mr. MacLeay, in the Horce Entomological , from an erroneous idea relative to the larvae of the