388 SYSTEM OF INSECTS. 



of the neuration of the wings in Perla is taken from the 

 Neuroptera, 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 Perla, 

 though membranaceous a circumstance occurring even 

 in Coleoptera are of a Neuropterous type; while the 

 angular termination of the cheeks in the Phryganeae 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 c , that of 

 Pliryganea 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. t. xxxii. /. 13. t. xxxiv./. 16. De 

 Geer vi. 169. t. x./. 7, 8. 



JV. 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 mandibulse, 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, 

 Kid. 505. 



