NO. 2057. THE GRASSHOPPER MICE—HOLLISTER. 445 



and in the Eio Grande Valley to northern Costillo County, Colorado. 

 West to Kanab, Utah, and Flagstaff, Arizona; east in New Mexico 

 to Santa Fe and the Sandia Mountains; south to Acoma and the 

 Zuni River. 



General characters. — A bright colored race; in perfect pelage rich 

 pinkish-cinnamon above. Much lighter colored than ruidosx, 

 fuliginosus, or capitulatus, its geographical neighbors. Darker and 

 richer colored than arcticeps, of the Great Plains. 



Color. — Adult in full winter pelage (57201, Bluff City Utah, Novem- 

 ber 8): Upperparts pinkish-cinnamon, fuiely Hned with darker 

 brownish; darkest on top of head, lower back, and rump; lower 

 sides and hips almost pure pinkish-cinnamon. Nose hghter than 

 head; ear tufts pale buffy; ears blackish, rimmed with white; 

 eyebrows dark brown; tail pale brownish-gray at base above, tip 

 and below white. Entire underparts pure white, hairs of lower 

 breast, belly, and sides with underfur narrowly pale slate-gray. 

 Adult in late spring (186479, Moki Pueblos, Arizona, May 18; type 

 of "paUescens"): Much faded and paler than in fresh coat, the rich 

 pinkish-einnamon faded to cinnamon-buff and the darker hair tips 

 of back much worn away; ear tufts less conspicuous than in winter. 

 Juvenile (166709, Kanab, Utah, September 21): Ahnost precisely 

 like the young of 0. I. arcticeps, but very slightly paler, the face 

 Hghter, and the underparts pure white. Paler than young of 0. I. 

 ruidosse. Young adult (161202, Kanab, Utah, September 20): 

 Much grayer than old adults in fall, without pinkish-cinnamon on 

 back and sides. Above drab, finely Uned with darker; the back 

 and rump hghtly washed with a glossy cimiamon-drab. Underparts 

 white. 



Many old adults, among them some of the oldest specimens exam- _ 

 ined, with the teeth very much worn, do not acquire the bright 

 pinkish-cinnamon pelage, even in winter, but remain in a coat much 

 like that of the young adult and immature but darker. Since I have 

 found no evidences of real dichromatism in the exammation of many 

 himdreds of specimens of OnycTiomys, and in every form each differ- 

 ence of color has proved a step in a true sequence of pelages, moults, 

 and wear, I am incUned to beUeve that this single case of what 

 otherwise might be regarded as dichromatism is in reahty a senile 

 pelage. Aged animals, in other words, appear not to renew into 

 the higlily colored fresh pelage of adults in the prime of hfe, but 

 take on a pelage resembling that of the immature. 



SJcull. — Essentially as m ruidosse. (Plate 15.) 



Measurements. — Averages and extremes of 12 adults from Utah 

 and Colorado: Total length, 154 (145-163); tail vertebrae, 44 (39-55); 

 hind foot, 21.9 (21.0-23.0); ear from notch in dry skin, 14.7 (13.9- 



