THE GROUND SQUIRRELS OP CALIFORNIA. 



665 



The enemies of this species of squirrel probably include most of the 

 carnivores of the high mountains. A Mountain Weasel (Mustela ari- 

 zonensis) has been seen to kill one by biting it through the back of the 

 neck (C. L. Camp, MS). 



The Belding Ground Squirrel bears no decided economic importance, 

 save as might be involved in the grass it eats. Its habitat falls only 

 within the summer range of sheep and cattle, and its numbers are 

 nowhere so great as to be likely to reduce the crop of pasture grass 

 to any material extent. 



STEPHENS SOFT-HAIRED GROUND SQUIRREL. 

 Citellus mollis stephensi (Merriam). 



Other names. — Stephens Spermophile ; Picket-pin, part ; Stephens Ground Squir- 

 rel ; Spermophilus mollis stephensi. 



Field characters. — Small size combined with very short and slender tail and gray 

 coloration (no stripes or special markings) ; ear small; length of body alone about 6£ 

 inches, with tail about 2 inches more. 



Description. — Nearly full-grown young in summer pelage (June) : General tone 

 of coloration on upper surface of body, buffy gray ; top of head from nose to hind 

 neck, pale cinnamon-buff, deepest on nose, and changing into color of back on 

 shoulder; cheek to shoulder, olive-buff; eyelids white; whiskers black; back light 

 drab with a faint effect of fine dappling ; the hairs on the back lead-colored at extreme 

 bases, then gray, then bister, and tipped with buffy white. Upper surfaces of feet 

 dull white ; palms naked ; soles of hind feet clothed with dull whitish hairs to about 

 halfway forward from heel ; claws blackish, with horn-colored tips. Tail flat-haired, 

 but narrowly so, and tapering from base to tip; upper surface buffy drab; beneath 

 dull white at base, becoming dusky pinkish buff toward end. Lower surface of body 

 silvery white, faintly buff tinged, particularly as forming a band along each side, and 

 with much of the leaden-hued bases of the hairs showing through. 



We have at hand but two specimens of this ground squirrel, and these are both 

 immature. 



Color variations. — A considerable series of specimens of Citellus mollis (sub- 

 species?) at hand from northern Nevada make it seem likely that stephensi varies 

 in color but little from the coloration as here described ; probably old adults are 

 grayer, with little or none of the cinnamon-buff about the head. The summer pelage 

 at all ages is notably soft and silky as compared with that of most other species of 

 ground squirrels at the same season. There is possibly a distinct winter pelage, with 

 regular molts in spring and fall ; but we have no specimens to indicate this. 



One of our two specimens has the tail much flatter, and broader ended, than 

 the other; but this we think is due to the way the tail was wired when the skin 

 was prepared. The usual thing is for the tail to taper from base to tip, thus quite 

 unlike the condition found in the Mohave Ground Squirrel. 



Measurements. — Nine specimens from the head of Owens Valley, in California, 

 average, in millimeters as follows : total length, 212 ; tail vertebrae, 50 ; hind foot, 

 32.4 (Merriam, 1898, p. 70). 



The two immature specimens in the Museum of Vertebrate Zoology, from near 

 Mono Lake, measure as follows, the first figures given being for the male, the second 

 for the female : total length, 195, 185 ; tail vertebrae, 45, 45 ; hind foot, 32, 32 ; ear 

 from crown, 4, 4 ; greatest length of skull, . . ., 35.6 ; zygomatic breadth, 21.8, 22.0 ; 

 interorbital width, 7.4, .... 



Weights. — Our two specimens weigh, in grams, as follows: male, 83.6; female, 78.0 

 (in ounces, about 3 and 2f, respectively). 



Type locality. — Queen Station, near head of Owens Valley, Nevada tin Esmeralda 

 County, just across California boundary] (Merriam, 1898, p. 69). 



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