METAMORPHOSIS. 77 



or poisers. The breeze-fly, p. 25, and all two-winged 

 flies, are examples. 



2. By passing through a necromorphous state, — 



NECROMORPHA ; 



In which the penultimate state is provided with mouth and 

 organs of locomotion, detached from the body, but so en- 

 veloped in a case that it can employ neither. The resem- 

 blance therefore to the perfect insect is very considerable, 

 except in the total want of motion. This group contains 

 two classes of insects. 



Class III. Hymenoptera ; in which the perfect insect 

 has four fully developed wings, all of them transparent 

 or membranous, and without scales. The honey-bee, 

 p. 40, and bees and wasps generally, are examples of 

 this class. 



Class IV. CoLEOPTERA ; in wliich the perfect insect has 

 two fully developed wings, and two wing-cases which 

 cover the wings. The sexton beetle, p. 53, and all 

 other beetles, are the examples. 



3. By passing through an isomorphous state, — 



ISOMORPHA; 



In wliich all the states are active and voracious, and of si- 

 milar form. Tins group contains two classes of insects. 



Class V. Orthoptera; in which the perfect insect has 

 four wings, the first pair being leathery, of little use in 

 flight, and often very minute and scarcely apparent; 

 the mouth is furnished with two strong mandibles, 

 meeting transversely. Crickets, p. 73, and grasshop- 

 pers are the examples. 



