1920] Crampfon — Lower Lepidopiera and Trichoptera ■ 27 



like that labeled "cm" in the Trichopteron (Fig. 3). On the 

 other hand, the merocoxa "me2" of Fig. 3 extends only part way 

 down the remainder of the coxa in all of the Trichoptera which I 

 have examined, and in all of them there occurs a inesothoracic 

 basicoxite "cm" (Fig. 3) ivhich is absent in all of the Lepidoptera I 

 have seen. Since these features seem to be constant in the groups 

 under discussion, they are probably diagnostic for the orders in 

 question, and by applying this test to the micropterygids, they are 

 seen to be clearly Lepidoptera and not Trichoptera! I would 

 especially emphasize the importance of this apparently conclusive 

 test, since it is the only feature (of which I have any knowledge) 

 which holds good in all cases examined, and on this account it should 

 be of great diagnostic value in attempting to determine whether 

 an insect is lepidopterous or trichopterous. 



The tergal region of the thorax is very similar in the lower 

 Lepidoptera and Trichoptera (Figs. 5 and 8), but the mesothoracic 

 scutellum of Mnemonica (Fig. 8, "SI2"), as is the case in most of 

 the other Lepidoptera, tends to become somewhat "transversely 

 oval" in outline, w^hile that of the greater part of the Trichoptera 

 (Fig. 5, "SI2") is more triangular in outline. This feature may also 

 prove to be of diagnostic value; but I doubt that it will be found 

 to hold in all cases, although I have been unable to find any excep- 

 tions thus far. In most Lepidoptera examined, there occurs a 

 tegula-bearing rod labeled "t" in Fig. 8 of Mnemonica; but I do 

 not find exactly this type of structure in most of my caddice-fly 

 material. Both of these primitive representatives of the orders 

 Trichoptera and Lepidoptera have a wing-coupling apparatus of 

 the jugo-frenate type (i. e. both jugum "j" and frenulum "fr" are 

 present in the insects shown in Figs. 5 and 8) so that Tillyard's 

 distinction between the two orders on this score, will not hold. 

 Since I have not made a study of the wing veins, I shall not attempt 

 to discuss this phase of the matter; but so far as the nature of the 

 jugum-bearing region "jf " and the alar ossicles "np," "ba," "a," 

 etc., are concerned, the basal portions of the wings, like the tergal 

 sclerites, are strikingly similar in the two insects under discussion. 

 In all of the Trichopterous larva* which I have examined, homo- 

 logues of the styli or gonopods (" s" of Fig. 6) are to be found in the 

 posterior region of the abdomen; but I have been unable to find 

 these structures in any lepidopterous larvae, and since the larvje of 



