SYSTEM OF INSECTS. 379 
them for mastication, as the Hymenoptera, or that take 
their food by suction, this part is replaced by a mostly 
narrow collar, forming a part of the alitrunk?. The ex- 
istence then of the prothorax in the Perlid@, and of the 
collar in the Trichoptera, affords no slight presumptive 
evidence that they belong to different Orders. Another 
circumstance that weighs much with me is, that the type 
of the neuration of the wings in Peria is taken from the 
Neuroptera, in the Trichoptera from the Lepidoptera ; 
the same observation extends to the legs of both», and 
likewise to the abdomen. Even in their oral organs, as 
far at least as relates to their mandibles, those of Perla, 
though membranaceous-—a circumstance occurring even in 
Coleoptera—are of a Neuropterous type; whiletheangular 
termination of the cheeks in the Phryganee approaches 
to the Lepidopterous mandibular rudiments. The prin- 
cipal argument on which Mr. MacLeay’s opinion seems 
to rest, is, that the larvee of both are aquatic, and clothe 
themselves in cases formed of various materials: but 
though this circumstance shows that they approximate 
in the system, it does not prove that they belong to the 
same Order, since the general habit and appearance of 
the two animals when arrived at perfection contravenes 
it. The larvee of Myrmeleon and of Leptis Vermileo form 
pitfalls of sand for their prey, and when they become 
pupz, cover themselves with it‘; but this in them does 
not even prove an affinity, but only an analogy. The 
larva of Perla is carnivorous‘, that of Phryganea F. 
* Vor. IIL. p. 548—. > The location of the legs to- 
gether, their long cox, and their calcaria, are analogous also to 
those of the Lepidoptera. - © Reaum. vi. Mem. x. é, xxxil. 
f. 13. £. xxxiv. f.1—6. De Geer vi. 169—. t. x. f. 7, 8. 
d N. Dict. d Hist. Nat. xxv. 286. 
