882 MONOGRAPHS OF NORTH AMERICAN RODENTIA. 
Different specimens vary in respect to the purity and darkness of the 
gray on the head and buttocks and in the depth of the yellowish-brown of 
the upper surface, which latter ranges from pale yellowish-brown to ochry- 
brown. The Pembina specimens average considerably larger and paler than 
those from Illinois and Wisconsin and Southern Minnesota. While the 
southern specimens do not exceed 9.00 in length, the Pembina specimens 
range generally above 10.00. 
This species is one of the most strongly marked of the genus, and can- 
not, by any possibility, be confounded with any other. It was first described 
by Sabine in 1822, and subsequently by Richardson, Kennicott, and Baird. 
“Though a common animal of the prairies of Northern Illinois and Wisconsin, 
it was unknown even to Audubon and Bachman, as late as 1851, except from 
Sabine’s and Richardson’s descriptions, and a specimen brought in by 'Town- 
send and supposed to have been taken ‘‘near the Columbia River”. All 
the earlier descriptions were based wholly on the accounts given by Sabine 
and Richardson. It has hence fortunately escaped synonyms. It is confined 
toa narrow belt of country, and specimens are still of rather rare occurrence 
in collections. Mr. Kennicott, in the Agricultural Report of the Patent . 
Office, has given an excellent and very detailed account of its habits. 
It was first described from specimens collected at Fort Enterprise, in 
about latitude 64°. Sabine also gives it as occurring at Cumberland House. 
Richardson states that he met with it only in the neighborhood-of Carlton 
House, “where it lives in burrows dug in the sandy soil, amongst the little 
thickets of brushwood that skirt the plains”. He states that it awakens from 
its winter's sleep about three weeks later than does S. richardsoni, which he 
thinks may be due to the snow lying longer on the shady places it frequents 
than on the open plains inhabited by the latter. 
Mr. Donald Gunn, in notes transmitted with specimens to the Smith- 
sonian Institution, states that its range does not extend much to the eastward 
of Lake Winnipeg, but that it is numerous to the westward of the lake, 
where it does considerable injury in the wheat-fields, hoarding up the grain 
in its burrows for winter use. He says it begins to hibernate about the 
first of November, and does not reappear till the snow is off in the spring. Dr. 
Coues found it abundant in the vicinity of Pembina; it also occurs in Minne- 
sota and over the prairie regions of Wisconsin, Illinois, Missouri, and Iowa. 
Mr. Kennicott also states that Dr. Hoy met with it in Eastern Kansas, and 
that it is found much further south in Illinois and Missouri than S. /ridecem- 
