12 



MAMMALS IN THEIR RELATION TO SPOTTED FEVER. 



Pig. 2. — Pine squirrel (i^iciurus hud- 

 sonicus richardsoni) . (About | 

 natural size.) 



of these ticks were Dermacentor venus- 

 ti(s, but several seeds and nj^mphs 

 belonged to the genus Ixodes. Pine 

 squirrels sometimes enter camps and 

 houses, and might carry ticks with 

 them. They are active throughout the 

 year, living in hollow trees or nests in 

 the branches. They are readily shot 

 and trapped and undoubtedly could be 

 destroyed with poisoned grain or nuts. 



* YELLOW-BELLIED CHIPMUNK. 

 (Eutauiias 1 Htcircntris.) 



These yelloAv-bellied chipmunks are 

 common in suitable places throughout 

 Bitter root Valley and the adjacent 

 foothills and up to 4,500 feet on warm 

 slojoes. They are to be found in all 

 sorts of country except the open sage- 

 covered bench land on the east side of 

 the valley, and usually occur wherever 

 the fever tick flourishes. In the spring 

 of 1910 the chipmunks first began to 

 emerge from hibernation on March 17, 

 and by the early part of April were 

 out in full numbers. In autumn they 

 were reported as entering hibernation 

 again about Thanksgiving. Most of 

 those taken in good " tick country " 

 proved to be infested with nymphs, or 

 seeds, of the fever tick (Dermacentor 

 venustus). One hundred and twelve 

 were examined. 



* WHITE-BELLIED CHIPMUNK. 



{Eutamias quadriuittatus umbrinus.) 



The white-bellied chipmunks occur 

 in the mountains mainly above the 

 range of the last species. They in- 

 habit open rocky hillsides, old burns, 

 where there is plenty of fallen timber, 

 and rock slides, from about 3,700 feet 

 to 8,100 feet altitude, in the mountains 



