GENERAL STRUCTURE 



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FiQ. 149. Digestive tract of Argas persicus; an., anus; eh., chelicera; int. c, 

 intestinal coeca; ces., oesophagus; ph., pharynx; sal. gl., salivary glands; St., 

 stomach. X about 20. (Adapted from Robinson and Davidson.) 



-chel. 



Fig. 150. Head or capitulum of tick; 

 hyp., hypostome; chel., chelicera; pal., 

 palpus; has. p., basal piece. (Partly after 

 Banks.) 



Fig. 151. Tip of chelicera of a tick, 

 much enlarged; cut. p., articulated 

 cutting part; shaft, shaft; sh., sheath; 

 fl. t., tendon of flexor muscle; ex. t., 

 tendon of extensor muscle. (After 

 Nuttall, Cooper and Robinson.) 



