32 PARASITOLOGY. 



The leg^s are thick and strong, terminating in two 

 booklets or claws. The posterior pair are the long- 

 est, giving them great power to jump. 



Life Cycle. — The eggs are ovoid in shape and 

 brown in color ; they hatch in from six to twelve 

 days, depending upon the temperature. The larvae 

 are worm-like and are composed of thirteen seg- 

 ments. The mouth parts are arranged for mastica- 

 tion. The larval stage lasts about eleven days ; they 

 then pass their pupal stage in tough brown cocoons. 

 The cocoon stage lasts about fourteen days. 



Fleas breed in filth, carpets, rugs, kennels and 

 barns. 



Animal Infested. — Man. 



Injury to Host. — In the adult state they attack the 

 skin. The puncture causes itching and inflammation. 



Treatment.— Cleanliness; pyrethrum or tobacco 

 dust sprinkled in the infested quarters. 



PuLEX Serraticeps ( Scco — to cut). 



Synonym. — Ctenocephalus Canis, dog and cat flea 

 (Fleon — to flee). 



History. — Universally found. 



Descriptio7i. — Similar in appearance to the Pulex 

 Irritans, with the exception that it is provided with 

 fifteen to eighteen spines on the posterior margin of 

 the pro-thorax. In the preceding species the thorax 

 is entirely nude. 



Life Cycle. — Eighteen to twenty eggs are laid in 

 some dirty or dusty corner, which pass through the 

 same stages as the preceding species. 



Animals hifested. — They attack the cuticular sur- 

 face of dogs, cats and men. 



Treatment. — Dogs can be dipped in a five per-cent 



