416 FLEAS 



Dog and Cat Fleas. Next in importance to the human flea 

 as a parasite of man is the dog flea, Ctenocephalus canis, and the 

 closely allied cat flea, C. felis. In the southeastern United States 

 where the flea scourge is as great if not greater than in Cali- 

 fornia, the dog flea is the species usually met with. During the 

 moist hot summers this species becomes exceedingly abundant. 

 Although primarily a parasite of dogs this flea willingly includes 

 man in its bill of fare if opportunity offers, and also attacks 

 cats, rats and other mammals. The usual fleas of cats, how- 

 ever, are now generally considered to be specifically distinct from 

 the dog flea. The cat flea is the only one of the two species 

 found in India, where it is a common parasite of dogs as well 

 as cats. The cat flea has a longer and more slender head than 

 its near relative. Both species can readily be distinguished 

 from any other common species with similar habits by the pres- 

 ence of two conspicuous combs, one along the ventral margin of 

 the head, the other on the pronotum (Fig. 179B). 



The eggs of dog and cat fleas are usually laid loosely in the fur 

 of their host, whence they readily fall out when the host shakes 

 himself or is settling himself for a nap. They develop in the 

 dust and dirt of kennels, woodsheds, house floors or other places 

 where infested animals are likely to go. Houses, of course, be- 

 come infested through the agency of infested animals, and since 

 the fleas, once in houses, encounter man more readily than they 

 do the original hosts, man is very likely to suffer from their at- 

 tacks. Patton and Cragg found the inside of a hat, in which a 

 kitten had slept overnight, so full of flea eggs that it looked as if 

 it had had sugar sprinkled in it from a sifter. Another author 

 collected a teaspoonful of eggs from the dress of a lady who had 

 held a kitten in her lap for a short time. The writer has been 

 able to find a similar quantity of eggs by dusting a smooth hard- 

 wood floor after an infested dog had indulged in one vigorous 

 shake. With these instances in mind one can readily understand 

 how houses into which infested pets are admitted become over- 

 run with fleas. 



The dog flea, from its habits, is the species most frequently 

 implicated in the transmission of kala-azar (see p. 83), and is 

 the species usually instrumental in transmitting tapeworm 

 (Dipylidium) infection to children. Since this species will feed 

 on rats there is no reason for doubting that it may act as a trans- 



