816 MONOGRAPHS OF NORTH AMERICAN RODENTIA. 
tained near the sources of the Arkansas River. Mr. Say properly regarded 
it as a Ground Squirrel, though describing it as a Scturus. He says :—‘‘It is 
allied to the Sc. striatus, and belongs to the same subgenus ( Tamas, Illig ), 
but it is of larger size,” ete., ete. Dr. Richardson, in his excellent account 
of the species, transferred it to Spermophilus (regarded by him as a subgenus 
of Arctomys), to which genus it was afterward uniformly referred till 1874, 
when I again placed it in Tamas. i 
Up to a comparatively recent date, this has been a rare species in col- 
lections. Professor Baird, in 1857, was able to refer to but two examples, 
and few others had been seen by other naturalists. In the preparation of the 
present article, I have had access to upward of seventy specimens, nearly 
all of which have been collected since 1868, and most of them under the 
auspices of the present Survey. 
Its known range extends from Apache, Ariz. (Cowes and Yarrow), north- 
ward in the Rocky Mountains to latitude 57°, where, according to Richard- 
son, it was obtained fifty years ago by Mr. Drummond. As shown by the 
subjoined list of specimens, it has been met with by Dr. Elliott Coues in 
Northern Montana; by Dr. Hayden and Mr. W. 8S. Wood, in the Black Hills; 
by Mr. F. J. Huse, at Yellowstone Lake, Montana Territory; by Mr. C. H. Mer- 
riam, at Henry’s Lake, Idaho; by Dr. J. 8. Newberry and Capt. Charles 
Bendire, in Oregon; by Mr. J. Stevenson and others, in various parts of Col- 
orado; by Messrs. Ridgway and Bischoff, in Nevada; and by Capt. J. H. 
Simpson’s party, in the Sierra Nevada Mountains. Dr. J. G. Cooper also 
refers to it as ‘‘common” near the summits of the Sierra Nevada Mountains 
in latitude 36°, and Mr. H. W. Henshaw reports it as frequent in the mount- 
ains of Southern California. Dr. Coues has lately found it ‘very common” 
in the pine-belt of the mountains of Northern Colorado. It hence may be 
supposed to occur throughout the mountainous districts of the interior, from 
the Black Hills of Dakota westward to the Sierra Nevada and Cascade Ranges. 
It lives among rocks in wooded districts, and appears to be chiefly alpine in 
its distribution. Its habits closely resemble those of the Chipmunk (7. 
striatus) of the Eastern States, as was noticed by Mr. Say, and later by 
Dr. Newberry and other writers who have had the opportunity of observing 
it in life. 
