MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 55 



The first autbor to suggest the derivatiou of Lepidoptera and the Trlchoptera from a common 

 stem form was A. Speyer.' He speaks of the great similarity of tlie venation of the trichopterous 

 wings to those of the Hepialidie, Cossidre, Micropterygidte, and to the liind wings of the Psychidje, 

 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 raaxillie and labium, but does not 

 specially refer to the distinction in shape between the maxilhc of the two orders. Speyer does 

 not believe that the Lepidoptera 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 in the imago state had through disuse slightly 

 developed biting month 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 in the 

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

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

 the corollas of flowers, became a hollow sucking organ. This view was also held by H. Miiller in 

 18G9, who claimed that " There is the closest affinity between the Phryganeida^ and Lepidoptera, 

 and the Phryganeidre have the buccal organs precisely in that rudimentary state which we 

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

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

 1871). 



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

 out that in the trunk characters, especially the thoracic, these insects were fundamentally nuich 

 less allied to the Lepidoptera than has been supposed. 



But in the mouth parts also we have a character of fundamental importance which still further 

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

 mandibles. This is the presence in the maxilla of Eriocephala of a lacinia, and of a true galea, 

 while the maxilla of Trichoptera entirely differs, having not only no lacinia, but a much reduced, 

 almost vestigial, galea,'' the maxillary palpi being very large. 



In respect, then, to the maxilla', the Lepidoptera are nearer the ametabolous, mandibulate 

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

 formed mandibles, and many others (Tineidne, Pyralidse, and CrambidiB) have vestigial ones. 



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 impossible that these insects 

 with their reduced prothorax and concentrated or fused meso and metathorax, together with their 

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

 ancestors of the Lejiidoptera. 



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

 have just quoted, that there is a close relationship between the Tipularia'. and the Lepidoptera, in 

 the similar venation of the wings in many Tipularia; (Limuobia, Ctenophora) and tlie Phryganeidie, 

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

 Tipuhie from the buccal organs of the PhryganeidiB than from those of any other order of insects." 

 By this statement he probably jneans the strong resemblance of the haustellum (rather a lapping 

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

 a point which needs further examination. 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 relationship between the two orders. 



'Eut. Zeitung, Stettin, J:ihrg. 31, p. 202, 1870. 



-The cases of a trichopterous insect have recently been discovered by Dr. Anton Fritsch iu the Permian beds of 

 Bohemia. K. bohm. Oesellschaft der Wissenschaften, 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 galea), Third Report United States 

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

 Muudwerkzeuge der Trichoptera, 1893. 



