76 PARASITOLOGY. 



tiis. The dorsal shield is slightly smaller, and is 

 light in color ; the palpi are short. In the male the 

 dorsal shield covers the entire dorsal surface. The 

 free extremity of the leg is provided with two hook- 

 lets and a fan-shaped organ, instead of the globule 

 shaped apparatus, as in the species Annulatus. 



Condition Produced. — They carry the protozoa pro- 

 ducing fever as Boophilus Annulatus does in the 

 United States. 



Dermacentor Electus (Derma — skin ; kentesis — puncture). 



Sy7ionyins, — Dog tick; wood tick; Dermacentor 

 Americanus. 



History, — Very common in the woods of the United 

 States. 



Animals Infested. — Dog, horse, ox, etc. 

 Description. — The engorged female is about the 

 size of the fever tick, though the legs are longer and 



Fig. 29.— Amblyomma Americanum Larva. Photomicrograph 1x2/3 



inch. 



a, Mandibles. c, Body. 



b, Legs. d, Palpi. 



