Produced by Chris Curnow, Joseph R. Hauser, Joseph Cooper and the Online Distributed Proofreading Team at http://www.pgdp.net Geographic Distribution of the Pocket Mouse, Perognathus fasciatus BY J. KNOX JONES, JR. University of Kansas Publications Museum of Natural History Volume 5, No. 29, pp. 515-526, 7 figures in text August 1, 1953 University of Kansas LAWRENCE 1953 UNIVERSITY OF KANSAS PUBLICATIONS, MUSEUM OF NATURAL HISTORY Editors: E. Raymond Hall, Chairman, A. Byron Leonard, Robert W. Wilson Volume 5, No. 29, pp. 515-526, 7 figures in text August 1, 1953 UNIVERSITY OF KANSAS Lawrence 1953 PRINTED BY FERD VOILAND, JR., STATE PRINTER TOPEKA. KANSAS 1953 24-7673 Geographic Distribution of the Pocket Mouse, Perognathus fasciatus BY J. KNOX JONES, JR. In his "Revision of the pocket mice of the genus Perognathus," Osgood (1900:18-20) reviewed the distribution, as then known, of _Perognathus fasciatus_ and recognized two geographic races--_Perognathus fasciatus_ [_fasciatus_] Wied-Neuwied in eastern Montana and Wyoming and adjacent parts of North and South Dakota, and _Perognathus fasciatus infraluteus_ Thomas, known only from the type locality at Loveland, Larimer County, Colorado. Later, Cary (1911:61) described _Perognathus fasciatus litus_ as a pale subspecies occurring in the lower Sweetwater Valley and adjacent parts of the Red Desert of south-central Wyoming. After 1911 no important taxonomic contributions dealing with _Perognathus fasciatus_ appeared. In studying the kinds of pocket mice known from Nebraska, I examined thirteen specimens of _P. fasciatus_ from the northwestern part of the state which did not agree satisfactorily with the descriptions of any known subspecies of _fasciatus_. This impelled me to examine material from the entire range of _P. fasciatus_. This examination revealed that: (1) _Perognathus callistus_ Osgood, heretofore considered to be a full species, should be reduced to subspecific rank under _P. fasciatus_; and (2) specimens from eastern Wyoming and adjacent parts of Montana, South Dakota and Nebraska represent an heretofore unrecognized subspecies. Further investigation, however, revealed that _Perognathus flavescens olivaceogriseus_ Swenk, described from northwestern Nebraska (Swenk, 1940:6), is not _flavescens_ but actually _fasciatus_. Since the specimens on which Swenk's description was based were taken within the range of this newly recognized subspecies, and since my examination of the holotype shows it to be of the species _Perognathus fasciatus_, the subspecific name _olivaceogriseus_ is available.