178 



DISEASES DUE TO BACTERIA 



and an unpaired bristle which, opposing- iisdf lo these, forms am 

 afferent tube for sucking blood. 



The three pairs of legs with their paired claws are long and strong. 



The abdomen has ten segments; the last three arc modified for 

 sexual purposes. 



The male has on the ninth segment large claspers and a large 

 complex penis. 



Pttlex itf-ilans. 14/1. 



Larva of flea. Enlarged. 

 (After Railliet.) 



Pulex serraticeps. 22/1. 



ALIMENTARY TRACT. 



In the head is an elastic pharynx acting like a suction pump ; its 

 cavity, when expanded by the contraction of certain muscles, forms a 

 vacuum. 



The stomach is very distensible, the rectum is large. They carry- 

 two pairs of salivary glands. 



REPRODUCTION. 



The eggs are large, dropped casually in places where domestic 

 animals sleep, hatching in two to fourteen days according to tempera- 



