LEPIDOPTERA, HEMIPTERA, DIPTERA. 427 



similar texture, of which the hinder are the largest, 

 with narrow, meshed netted veins. 



4. Lepidoptera — Butterflies and moths. These 

 undergo a perfect change of form ; have a mouth 

 with a spiral trunk, furnished with a piercer, or 

 sucker, and not capable of biting; four wings, of 

 similar texture, wholly or only partly covered with 

 fine dust-like scales ; the larvae are caterpillars, and 

 have six true legs, and from four to ten fleshy pro- 

 legs ; pupae, with the cases of the wings and of the 

 legs indistinct, and soldered to the breast. 



5. Hemiptera — Bugs, locusts, plant-lice. These 

 have an imperfect change of form. The mouth is 

 armed with a beak, furnished with a piercer, or 

 sucker, and not capable of biting. They have four 

 wings, generally standing up, when at rest, like the 

 roof of a house, and frequently all of the same mem- 

 braneous texture. The larvae and pupae are nearly 

 like the adult insect, but are wanting in wings. 



6. Diptera — Mosquitos, gnats, and flies. The^e 

 undergo a perfect change of form ; the mouth has 

 a proboscis for sucking, sometimes having small 

 lancet-like appendages for piercing concealed inside 

 the trunk, as in the horse-fly. They have two 

 naked, transparent wings, and in place of the two 

 hind wings a slender stalk-like appendage on each 



