INSECTS AFFECTING MAN AND ANIMALS 187 



wingless, have the body strongly compressed laterally, are 

 provided with sucking mouth-parts, and have strong hind 

 legs which enable them to jump considerable distances. 

 The female lays her eggs in the hair of the dog or cat, from 

 which they become scattered, and the young develop in 

 cracks of the floor, under carpets, in rubbish, etc. In such 



FIG. 132. Cat and dog flea (Ctenocephalus canis). (After U. S. Dept. 



Agr.) 



a, egg; 6, larva in cocoon; e, pupa; d, adult; e, mouth-parts of same from 

 side; /, antenna; g, labium from below, b, c, d, much enlarged, a, e, f, g, more 

 enlarged. 



situations the larvae feed on either animal or vegetable mat- 

 ter. The larvae are slender, worm-like creatures, scarcely 

 an eighth of an inch long, are quite active, and become grown 

 in about two weeks. They then spin delicate, silken co- 

 coons, in which they transform to pupae and from which the 

 adults emerge in a few days. In warm, damp weather a 

 whole generation may develop in a fortnight, although or* 



