TICK BITES 



357 



lairs or abodes of their hosts. The Ixodidse, on the other hand, 

 inhabit the hosts rather than their lairs, and frequently remain 

 attached for several days, or even longer. In the less capacious 

 Argasidse the females lay their eggs in a number of installments 



FIG. 154. Comparison of dorsal and ventral view of Ixodid and Argasid females; 

 A, dorsal view of Ixodid 9 I A', ventral view of same; B, dorsal view of Argasid 

 9 ; B', ventral view of same. An., anus; cap., capitulum; d. sh., dorsal shield; 

 e.s., eye spot; gen. op., genital opening; sp., spiracle. 



after successive feeds, and the total number of eggs may be 

 counted in hundreds instead of thousands. The reason for this 

 difference is readily accounted for by the. difference in habits in 

 the two families, since the progeny of the Argasidae, reared in 

 the lairs of the hosts, have far better chances of finding a host and 

 of surviving than do the progeny of the Ixodidae which live on 

 their hosts and may drop off to lay their eggs almost anywhere 

 in the wanderings of the host. 



Tick Bites. The status of ticks as human parasites, as stated 

 before, is one not to be passed over lightly. Aside from the 



