178 



DISEASES OF 



In Fig. 69 is seen the head of one of the ticks, en- 

 larged 50 times, and in Fig. 71 is seen a dog tick of 

 natural size and in Fig. 70 same enlarged after feeding. 

 These parasites do not seem to cause a great amount of 

 suffering as nearly all sheep seem to be affected with 

 them without ever noticing their presence. Each 

 species of -domestic animals has its peculiar species of 

 tick, each being different from the other. 



LICE. 



Most of these parasites have the mouth arranged so 

 as to act as suckers, and many of the species have only 

 one claw on each foot, as will be seen on referring to 

 Fig. 73. 



Fig. 72. Horse louse. 



Fig. 73. Ox louse. 



