634 



ZOOLOGY 



SECT. 



rostrum formed from the labium, enclosing the jaws in the form of 

 piercing organs. The prothorax is free from the other segments 

 of the thorax. The metamorphosis is incomplete. 



FIG. 510. Cicada. (After Guerin and Percheron.) 



This order includes Bugs, Water-bugs, Lice, Scale-insects, Plant- 

 lice (Fig. 509), and Cicadas (Fig. 510). 



ORDER 5. DIPTERA. 



Insects provided (except in the Fleas) with a single pair of 

 transparent membranous wings, 

 representing the anterior pair of 

 other orders. The mouth parts are 



FIG. 511. Culex (mosquito) and larva. 

 (After Guerin and Percheron). 



FIG. 512. Bot-fly of j the^horse (Gastro- 

 philus equi). a.v-inature insect ; b, 

 egg attached to a hair ; c, d, and e, stages 

 in the larval development. (After Brehm.) 



adapted for piercing and sucking. The prothorax is fused with the 

 other segments of the thorax. There is a complete metamorphosis. 



