160 



skin of the host, and a firm hold is thus secured. The 

 wound is deepened by the simultaneous action of the 

 chelicerae or mandibles, which are cutting stylets with 

 serrated ends. 



Hypostome 



Palp 



F(a. 33. The Grass or Sheep and Dog-tick of Europe ( Ixodes ricinus). 

 Dorsal aspect of Female, enlarged. Note the anterior position of 

 the Capitulum and mouth-parts. With permission, from " British 

 Museum (Natural History) Economic Pamphlet, No. 6." 



The mandibles have sheaths ; applied together, they 

 form the dorsal wall of the front portion of the buccal 

 cavity ; the ventral wall is formed by the hypostome. 

 The back part of the buccal cavity, into which the salivary 



Hypostome 



Palp 



~ Palp 



I Capitulum 



FIQ. 34. Capitulum and Mouth-parts of a Tick (Dorsal view). 



ducts open, is a sac-like extension behind the entrance to 

 the pharynx. 



The blood is drawn up the sucking-tube, which is formed 

 by the two mandibles and the hypostome closely applied 

 together. 



