ORDER ACARINA 



31 



some recorded instances are of individuals kept in confine- 

 ment for two years without food, but which moulted at 

 frequent intervals. 



The related Argas persicus occurs both in the old world 

 and America. It is a troublesome pest for chickens and is 

 credited also with attacks on human beings. 



Fig. 8. — Argas ?iiinialus. a tick which infests poultry. Greatly enlarged. 

 (Banks, Div. Ent., U. S. Dept. Ag.) 



The Cattle Tick (Margaropus annulatus). — The cattle tick, 

 as already mentioned, has received probably more atten- 

 tion than any other species, as it has been known for many 

 years as the carrier of Texas fever in cattle, and its great 

 importance to the cattle industry has been the occasion 

 for elaborate studies regarding its habits. In this species 

 the newly hatched tick locates as soon as possible upon 

 a warm-blooded animal, preferably upon cattle, as these 

 seem to be by all means the preferred host. Once located 

 they retain their attachment until mature. The females 

 when mature and gorged with eggs loosen their hold, drop 

 to the ground and eggs may be distributed wherever the 

 adults fall. The period of incubation differs greatly with 

 regard to temperature, so that the rate of development and 

 number of generations differ much at different seasons of 



