MAMMALS IN THEIR RELATION TO SPOTTED FEVER. 



13 



1. 



2. 



on both sides of the valley. This is one of the few small mammals 

 found on the goat rocks, and may serve as a host for many of the 

 seeds and nymphs of the fever ticks which in the adult stage feed on 

 the goats. Twenty-nine of these chii)munks— most of them taken in 

 poor tick country — 

 were examined and 

 only one tick was 

 found. This was a 

 nymph of Derma- 

 centor venustus. 



^ COLUMBIAN GROUND 

 SQUIRREL. 



( Citelliis col It inhian us. ) 



Columbian ground 

 squirrels ( commonly 

 called "picket pins") 

 are abundant 

 throughout the whole 

 length of the valley 

 and from the river 

 well up into the 

 mountains on both 

 sides. They were 

 taken on Sweeney 

 Creek up to 7,000 

 feet. I believe that 

 on the whole they 

 are very much more 

 numerous on the Avest 

 side of the valley, 

 for they are practi- 

 cally absent from the 

 wide belt of rolling 

 sagebrush benches on 

 the east side. In 

 the valley they seem 

 most numerous in 

 stony fields, although 

 abundant also in 



Fig. 3. — 1, White-bellied chipmunk {Eutamias quadrivit- 

 tatus umhriniis) ; 2, yellow-bellied chipmunk (Eutamias 

 luteiventris) . (About i natural size.) 



meadows, hayfields, and open pine woods. In the mountains they 

 prefer open-timbered southern slopes. They usually hibernate late 

 in August and begin to emerge from hibernation toAvard the end of 

 March. They were out in full force by the 10th of April. Between 



[Cir. 82] 



