Stages of Development 



All fleas pass through four stages, the adult, the egg, the larva, or 

 maggot, and the pupa, or resting stage. The adults are found on 

 animals or hopping about on the ground. The eggs are laid by the 



females while on the host and drop to 

 the ground and hatch in a few days 

 into legless larvae or maggots (fig. 

 4). In 2 weeks or more the larvae 

 become full-grown in the dust or sand 

 and then spin tiny cocoons, in which 

 they change to adult fleas in the course 

 of 1 or more weeks. 



Fleas often breed in tremendous 

 numbers in basements or outbuildings 

 where dogs, cats, or hogs are kept. 

 Even when dogs, cats, and other hosts 

 are taken away, the flea maggots pro- 

 ceed with their development, and the 

 resulting adults may live for several 

 weeks without food. This accounts 

 for the frequency with which people find their homes overrun 

 with fleas when thev return from a summer vacation. 



Figure 2.— Human flea (female), greatly 

 enlarged. 



Control of Fleas on Animals 



Dogs and cats can be kept practically free of fleas by occasionally 

 applying derris or cube powder next to the skin along the back and 

 neck and on top of the head. If animals have free run, this treatment 

 must be repeated every 2 weeks. A level teaspoonful is enough to 

 kill every flea on a large dog. For smaller animals the amount should 

 be reduced according to the size of the animal. Most derris and cube 

 powders are effective. Their insect-killing value depends largely on 

 the amount of rotenone they contain. They 

 should have at least 0.5 percent of rotenone 

 and should be finely ground. Much of the 

 powder now on the market contains 4 or 5 

 percent of rotenone. This may be diluted 

 with talcum powder so as to bring the 

 rotenone content down to 1 percent. These 

 materials kill slowly; do not expect to see 

 the fleas drop off dead immediately after an 

 application. 



If derris or cube is not at hand, fresh 

 finely ground pyrethrum powder (insect 

 powder) may be used as a dust. Pyrethrum 

 powder should contain not less than 0.9 per- 

 cent of pyrethrins; these are the insecticidal principles of pyrethrum. 



None of these materials are considered poisonous to domestic 

 animals, although cats are sometimes thrown off their feed by licking 

 the material from the coat. As the eyes are sensitive to derris and 

 cube, care should be taken not to get these powders into them. 



Figure 3— Sticktight flea (female), 

 greatly enlarged. 



