MEMOIES OF THE NATIONAL ACADEMY OF SCIENCES. 55 



The tirst author to suggest the derivation of Lepidoptera and the Tiichoptera from a common 

 stem form was A. Speyer.' He si)eaks of tlie great simihuity of tlie venation of tlie triohopterous 

 wings to tliose of the Hepialidit, Cossidi^e, Micropterygidre, aud to tlie hind wings of the Psyohidie, 

 though allowing that there is no Trichopteron whose venation entirely agrees with that of any 

 Lepidoptera. He points out the fact that there are certain moths whose pupa- have free limbs, as 

 Heterogenea, Adela, and Micropteryx, and that members of both orders spin a cocoon. He refers 

 to the dissimilarity in the mouth-parts of the two orders, the maxilhe and labium, but does not 

 specially refer to the distinction Iti shape between the maxilhe of the two orders. S|)eyer does 

 not believe that the Lepidoi)tera directly descended from the Trichoptera, but that they had a 

 common origin, the latter being the earlier to appear, their remains occurring iu lower geological 

 strata.- He thinks this common stem-form iu the imago state had through disuse slightly 

 developed biting mouth parts: that they took little or no nourishment, like the moths. The 

 duration in the adult life was probably short, and the ancestors of the Lepidoptera were iu the 

 larval state aquatic, like caseworms. He suggests that the outer lobe of the maxillae were at 

 first simple in shape, but in the course of time by adaptation to the slowly increasing depth of 

 the corollas of tlowers, became a hollow sucking organ. This view was also held l)y 11. ^liiller in 

 18G9, who claiilied that " There is the closest affinity between the Phryganeid:e and Lepidoptera, 

 and the Phryganeida^ have the buccal orgaus precisely in that rudimentary state which we 

 shoukl presuppose appropriate to the primordial race or type of Lepidoptera."' Miiller also claimed 

 that both Lepidoptera and Phryganeidte proceeded from a common stock. (Amer. Nat., v. 288, 

 1871). 



In a review entitled "The position of the caddis flies" (Amer. Nat., v, 707. 1S"1) we pointed 

 out that in the truuk characters, especially the thoracic, these insects were fundamentally much 

 less allied to the Lepidoptera than has been supposed. 



But in the mouth i)urts also we have a character of fundamental importance which still further 

 separates the two orders, notwithstanding the fact that both orders in the imago state lack 

 mandibles. This is the i^resence in the nmxilla of Eriocephala of a laciuia, aud of a true galea, 

 Avhile the maxilla of Trichoptera entirely differs, having not only no laeinia, but a much reduced, 

 almost vestigial, galea, ^ the maxillary pali)i being very large. 



In respect, then, to the maxilloe, the Lepidoptera are nearer the amctabolous, mandibulate 

 insects than the Trichoptera, while some genera of the former order (Eriocephala) have well- 

 formed mandibles, and many others (Tineida^, Pyralida^, and Crambida') have vestigial oues. 



In fact the venation of Eriocephala and of Micropteryx is in general remarkably like that of 

 Amphientomum, a generalized Psocid, and it is not altogether imjiossible that these insects 

 with their reduced jirothorax and concentrated or fused meso and metathorax, togetlier with their 

 maxillary fork, may have had some extinct allies which were related to the remote ametabolous 

 ancestors of the Lepidoiitera. 



Here might be recalled the suggestion of Hermauu Miiller iu the same address from which we 

 have just quoted, that there is a close relationship between the Tiinilariic and the Lepido^jtera, in 

 the similar venation of the wings iu many Tipularite (Limnobia, Ctenophora) and the Phryganeidai, 

 "and, finally, the circumstance that it is far easier to deduce morphologically the proboscis of the 

 Tipula- from the buccal organs of the PhryganeidiTe than from those of any other order of insects." 

 By this statement he probably jueans the strong resemblance of the haustellum (rather a lai)ping 

 organ than a sucker) of the Trichoptera to the lapping organ or proboscis of the Diptera, This is 

 a point which needs further examinatiou. The close similarity of the pupa of the more generalized 

 Diptera and of the more generalized Lepidoptera also needs to be emphasized, for it is suggestive 

 of an early close relationshiii between the two orders. 



lEnt. Zeitung, Stettin, Jahrg. 31, p. 202, 1870. 



■ The cases of a trichopterous insect have recently heen discovered hy Dr. Anton Fritsch iu the Permian beds of 

 Bohemia. K. liohm. Gesellschaft der Wissenschafteu, November 23, 1894. The earliest Lepidopterous remains, 

 referred to a sphinx and to Pterophorus, occur in Jurassic strata. 



'See our figure of the maxilla of Limnephilus, fig. 4, PI. LIX (lac should be i/alea), Third Report United States 

 Entomological Commission. 1883; also the much more detailed figures of K. Lucas iu his Beitriige zur Kenntniss der 

 Mnndwerkzeuge der Trichoptera, 1893. 



