586 U. S. NATIONAL MUSEUM BULLETIN 205 



1920. Microtus pennsylvanicus wahema V. Baileyf, Journ. Mamm., vol. 1, No 



2, p. 72, Mar. 2, 1920. (Glendive, Dawson County, Mont.) 



1943. Microtus pennsylvanicus insperatus Anderson, Canadian Field-Nat. 

 vol. 57, Nos. 4-5 (May ) , p. 92, Oct. 17, 1943. 



Type Locality. — Custer, Black Hills, Custer County, S. Dak. Range. — Semi 

 arid regions from southwestern South Dakota (and probably parts of north 

 eastern Wyoming), southwestern North Dakota (V. Bailey, North Amer. Fauna 

 No. 49 (1926), p. 94, Jan. 8, 1927) , eastern Montana, and parts of extreme south 

 western Saskatchewan and southeastern Alberta; intergrading with drummondii 

 over most of its range in Canada (Anderson, Nat. Mus. Canada Bull. 102 (1946) 

 p. 156, Jan. 24, 1947. See also Soper, Journ. Mamm., vol. 27, No. 2, p. 147 

 May 14, 1946) . 



Microtus pennsylvanicus drummondii (Audubon and Bachman) * 



1853. Arvicola drummondii Audubon and Bachman, The viviparous quadru- 

 peds of North America, vol. 3, p. 166. 

 1897. [Microtus] drummondii Trouessart,, Catalogus Mammalium .... fasc. 



3, p. 563. 



1899. Microtus stonei J. A. Allen, Bull. Amer. Mus. Nat. Hist., vol. 12, p. 5, 



Mar. 4, 1899. (Liard River, British Columbia, Canada.) 

 1913. Microtus pennsylvanicus drummondii Hollister, Canadian Alpine Journ., 



Special Number, p. 23, Feb. 17, 1913. 

 1940. Microtus pennsylvanicus rubidus F. H. Dale, Journ. Mamm., vol. 21, 

 No. 3, p. 339, Aug. 13, 1940. (Sawmill Lake, near Telegraph Creek, British 

 Columbia, Canada. Regarded as identical with drummondii by Rand, 

 Canadian Field-Nat., vol. 57, Nos. 7-8 (October-November 1943), pp. 115, 

 121, Jan. 24, 1944, and by Anderson, Nat. Mus. Canada Bull. 102 (1946), 

 p. 155, Jan. 24, 1947, and as a valid subspecies by Baker, Univ. Kansas 

 Publ. Mus. Nat. Hist., vol. 5, No. 9, p. 106, Nov. 28, 1951.) 

 Type Locality. — "Valleys of the Rocky Mountains"; probably in the vicinity 

 of Jasper House, Alberta, Canada. Range. — Rocky Mountains northward from 

 Crowsnest Pass, through central and northern British Columbia from mountains 

 east of Bella Coola, British Columbia, north to southern and central Yukon, to 

 mouth of Mackenzie River, Northwest Territories, following northern limit of 

 trees to lower Anderson and Horton Rivers, southeastward to Churchill, Mani- 

 toba, and Fort Albany on James Bay, and Lake Attawapiskat, Thunder Bay, and 

 Rainy River, in western Ontario; nearly the whole of Manitoba, all of Saskatche- 

 wan except in extreme southwest, and all of Alberta except in extreme southeast ; 

 intergrading with fontigenus in western Ontario, with aphorodemus in north- 

 eastern Manitoba, and with insperatus in semiarid parts of southern Saskatchewan 

 and Alberta (Anderson, loc. cit.) ; and southward to high glacial-prairie region 

 between Missouri and Red River Valleys of North Dakota (V. Bailey, North 

 Amer. Fauna No. 49 (1926) , p. 93, Jan. 8, 1927) , grading toward drummondii in 

 northwestern Minnesota (Swanson, Minnesota Dept. Conserv. Techn. Bull. 2, 

 p. 20, 1945). 



Microtus pennsylvanicus arcticus Cowan 



1951. Microtus pennsylvanicus arcticus Cowan, Journ. Mamm., vol. 32, No. 3, 

 p. 353, Aug. 23, 1951. 



