68 The Mammals of Colorado 
FIG. 25. PLAINS POCKET MOUSE, Peroguathus flavescens 
Skull, showing dentition, x 3I 
Perognathus flavescens (Lat. flavescere, to become yellow) . 
Plains Pocket Mouse. 
Perognathus fasciatus flavescens Merriam, N. A. Fauna, No. i, 
p. II (1889). 
Type locality. — Kennedy, Cherry Co., Nebr. (V. Bailey, June 11, 
1888). 
Measurements. — Total length, 5.1; tail vert., 2.4; hind foot, 0.7. 
Description. — (From a specimen taken at Colorado Springs, Dec. 
7): Above pale buff, moderately lined with black, except on sides, 
which are clear; under parts white; tail grayish white. The 
whitish tail distinguishes it from P. callistus, which otherwise re- 
sembles it quite closely. 
Distribution. — The Plains Pocket Mouse is recorded from Nebraska, 
Kansas, Colorado, South Dakota, and New Mexico. In Colorado, 
judging from the records at hand, it is confined to the plains region 
east of the mountains, being recorded from Boulder, Weld, Adams, 
Logan, El Paso, and Pueblo Counties. 
Perognathus callistus (Grk. kallistos, beautiful). Beautiful 
Pocket Mouse. 
Perognathus callistus Osgood, A^. A. Fauna, No. 18, p. 28 (1900). 
