Ewing — Significance of Parasitism in Acarina. 29 



I. ruhidus — Bassaris astuta. 



7. 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. 



EHIPICEPHALUS Kocll. 

 R. texanus Banks — Dogs, horses. 



MAKGAROPus Karscli. 



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



horses. 



AMBLYOMMA Kocll. 



A. amcricanum Linnseus — 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. tuberculatun Marx — Gopher, tortoise. 



DERMACElSrTOR Kocll. 

 D. albipictus Packard — Moose, wapiti, beaver. 

 D. bifurcattis Neumann — Wild cat. 

 D. nigrolineatus Packard — Deer. 

 D. nitena Neumann — Horses. 



D. occidentalis 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 



