Ewing — Significance of Parasitism in Acarina. 29 



I. ruhidus — Bassaris astuta, 



/. bicornis — Fells concolor, F. onca. Homo sapiens. 



I. texanus — Grey squirrel, Procyon lotor, 



HAEMAPHYSALIS Koch. 

 H. chordeilis Packard — Nighthawk, turkey, killdeer (?). 

 H. leporis-palustris Packard — Rabbits, quail, lark, 



KHIPICEPHALUS Koch. 

 R. texanus Banks — Dogs, horses. 



MAEGAROPus Karsch. 



M. annulatus Say — Cattle, rabbit, porcupine, man (?), moose (?), sheep, 

 horses. 



AMBLYOMMA Kocll. 

 A. americanum Linnaeus — Cattle, man, horses, hogs, dogs, goats, panther, 



wolf, some of the small mammals. 

 A. cajennense Fabricius — Cattle, horses. 

 A. maculatum Koch — Cattle, horses, dogs, fox, man. 

 A. tu'berculatun Marx — Gopher, tortoise. 



DERMACENTOR Koch. 

 Z>. alMpictus Packard — Moose, wapiti, beaver. 

 D. lifurcatus Neumann— Wild cat. 



D. nigroUneatus Packard — Deer. • 



D. nitena Neumann — Horses. 



D. occidentaUs Neumann — Deer, California ground squirrel. 

 D. parumapertus Neumann — Man, chicken (?), jack-rabbit. 

 D. variabilis Say — ^Man, dogs, cattle, various smaller animals. 

 D. venuatus Banks — Man, horse, and several small mammals. 



Of all the groups of the parasitic Acarina the Ixodoi- 

 dea, or ticks, have the widest distribution among host 

 species. Single species of the ticks have been reported 

 from hosts not only belonging to different families, but 

 to different orders and even classes. For example, 

 Ixodes ricinus Linn, has been found upon sheep, goats, 

 cattle, horses, deer, dogs, cats, fox ferrets, hedgehogs, 

 hares, rabbits, bats, birds, man and ground-squirrels. 



Such a wide spread distribution of the different species 

 as is presented in the ticks is unique in the Acarina. It 



