388 SYSTEM OF INSECTS. 
of the neuration of the wings in Pcrla is taken from the 
Ncuroptera, in the Trichoptera from the Lepidoptera ; 
the same observation extends to the legs of both a , and 
likewise to the abdomen. Even in their oral organs, as 
far at least as relates to their mandibles, those of Pcrla, 
though membranaceous — a circumstance occurring even 
in Coleoptera — are of a Neuropterous type; while the 
angular termination of the cheeks in the Phryganeoe ap- 
proaches to the Lepidopterous mandibular rudiments. 
The principal argument on which Mr. MacLeay's opi- 
nion seems to rest, is, that the larvae 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 perfec- 
tion contravenes it. The larvae of Myrmeleon and of 
Leptis Vermileo form pitfalls of sand for their prey, and 
when they become pupae, cover themselves with it b ; but 
this in them does not even prove an affinity, but only an 
analogy. The larva of Perla is carnivorous , that of 
Phryganea mostly herbivorous d : so that they are not 
precisely similar in their habits. Whether they resem- 
ble each other altogether, in their form, does not clearly 
a The location of the legs together, their long coxa?, and their 
calcaria, are analogous also to those of the Lepidoptera. 
b Reaum. vi. Mem. x. /. xxxii. f. 13. t. xxxiv. /. 1 — 6. De 
Geer vi. 169—. t. x.f. 7, 8. 
N. Diet. d'Hist. Nat. xxv. 286. 
d De Geer ii. 511 — . He however observes, that they often at- 
tack other insects : but the form of their mandibular, like that of the 
caterpillars of Lepidoptera, which also on some occasions become 
carnivorous (Vol.. I. p. 386), is fitted for a vegetable diet. De Geer, 
Ibid. 505. 
