Produced by Chris Curnow, Tom Cos, Joseph Cooper and the Online Distributed Proofreading Team at http://www.pgdp.net Geographic Variation in Red-backed Mice (Genus Clethrionomys) of the Southern Rocky Mountain Region BY E. LENDELL COCKRUM and KENNETH L. FITCH University of Kansas Publications Museum of Natural History Volume 5, No. 22, pp. 281-292, 1 figure in text November 15, 1952 UNIVERSITY OF KANSAS LAWRENCE 1952 ~University of Kansas Publications, Museum of Natural History~ Editors: E. Raymond Hall, Chairman, A. Byron Leonard, Edward H. Taylor, Robert W. Wilson Volume 5, No. 22, pp. 281-292, 1 figure in text November 15, 1952 ~University of Kansas~ Lawrence, Kansas PRINTED BY FERD VOILAND, JR., STATE PRINTER TOPEKA, KANSAS 1952 [Illustration: Union Label] 24-4369 Geographic Variation in Red-backed Mice (Genus Clethrionomys) of the Southern Rocky Mountain Region BY E. LENDELL COCKRUM and KENNETH L. FITCH In the course of the preparation of a synopsis of the North American terrestrial microtines by one of us (Cockrum), and the completion of a Master's thesis on the geographical variation of the red-backed mice of Wyoming by the other (Fitch) we had occasion to study the red-backed mice of the southern Rocky Mountain region (see figure 1). Results of these studies are the recognition of two heretofore unnamed subspecies of the red-backed mouse in the southern Rocky Mountain region, and a clarification of the taxonomic status of two additional kinds. +Clethrionomys gapperi galei+ (Merriam) 1890. _Evotomys galei_ Merriam, N. Amer. Fauna, 4:23, October 8. 1931. _Clethrionomys gapperi galei_, Hall, Univ. California Publ. Zool., 37:6, April 10. 1897. _Evotomys gapperi galei_, Bailey, Proc. Biol. Soc. Washington, 11:126, May 13. _Type locality._--Ward, 9500 feet, Boulder County, Colorado. _Range._--The Rocky Mountains of extreme southern Alberta, Montana, northwestern and southern Wyoming, and north and central Colorado.