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 while the 



female is on the host and drop to the 

 ground, where they hatch in a few 

 days into legless larvae (fig. 4). In 

 2 weeks or more the larvae become 

 full-grown, and then spin tiny cocoons, 

 in which they change to adult fleas in 

 a week or more. 



Fleas often breed in tremendous 

 numbers in basements or outbuildings 

 where dogs, cats, or hogs are kept. 

 Even when the hosts are taken away, 

 the flea maggots proceed 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 they 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 amoimt 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 

 percent of pyrethrins; 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. 



DDT will destroy fleas on animals. It is most conveniently applied 

 to dogs as a 10-percent powder distributed next to the skin on the head, 

 neck, and back as described for derris or cube. A tablespoonful is 



Figure 3.— Sticktight flea (female), 

 greatly enlarged. 



