Vol. 35, pp. 105-106 October 17, 1922 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



A NEW POCKET MOUSE FROM IDAHO. 

 BY E. A. GOLDMAN. 



The common pocket mouse, Perognathus parvus and sub- 

 species, has a wide range in the arid interior from southern 

 Washington south along the eastern side of the Sierra Nevada 

 to southeastern Cahfornia, and eastward through Idaho and 

 Nevada to Wyoming. Shght, irregular, geographic variants 

 in size and color are numerous and several fairly well-marked 

 subspecies have been recognized. The discovery of the new 

 form described below is one of the results of recent field work 

 in the extensive but little known lava fields, in the Snake River 

 desert region of southern Idaho. 



Perognathus parvus idahoensis, subsp. nov. 



IDAHO POCKET MOUSE. 



Type from Echo Crater, 20 miles southwest of Arco, Blaine County, 

 southern Idaho. No. 236,394, d^ adult, U. S. National Museum (Bio- 

 logical Survey Collection), collected by L. J. Goldman, June 14, 1921. 

 Original number 2752. 



Geographic distribution. — Known only from the type locality. 



General characters. — Size large; color darkest of the known forms of Pero- 

 gnathus parvus; back blackish; lighter element in pelage of upperparts light 

 vinaceous buffy, most like P. p. parvus in general tone (not light ochraceous 

 buffy as in P. p. olivaceus), the blackish admixture strongly predominant; 

 skuU large, and very broad. 



Color (type). — Upperparts finely mixed light vinaceous buflf' and black, 

 the black predominant especially over lower part of back, and the buffy 

 element purest along lateral line of sides; chin, throat, and inner sides of 

 forearms dull whitish; chest pure white to roots of hairs; belly and inner 

 sides of hind legs overlaid with light ochraceous buff; the under color light 

 plumbeous; outer sides of forelimbs dusky, the dark color here continuous 

 with that of sides; heels black; ears blackish, except marginal white spots, 

 which by contrast are conspicuous; feet white; tail clothed above with 



iRidgway, Color Standards and Nomenclature, 1912. 



22— Proc. Biol. Soc. Wash., Vol. 35, 1922. (105) 



