richahdson's spermophile. 59 



females the teats numbered ten, indicating that larger litters of young 

 may sometimes be produced. 



I have heard the voice of this sperinophile on but one occasion, when 

 I mistook it first for the voice of the Striped Spermophile, but after catch- 

 ing the animal it occurred to me that the voice was higher and more 

 like that of the Sonoran Spermophile (SpermopMlus spilosoma), to which 

 this species is most nearly related. However, there is so little differ- 

 ence between the voices of 8. tridecemlineatus and 8. syilosoma that 

 the one might be mistaken for the other unless careful attention be 

 given them by one familiar with both. 



Food. — Of the food habits of this species we know very little. The 

 stomach of one specimen that I examined at Kennedy, Nebr., ^pril24, 

 1888, contained seeds and the remains of some young mice. The stom- 

 ach of another taken on the same day contained seeds and insects. 

 Other stomachs examined contained seeds, green herbage, and insects. 

 From these few examples it would seem that their food is nearly as 

 varied and of much the same nature as that of the Striped Spermophile. 



From an economic point of view this species is not of great importance 

 from the fact that it is not numerous in farming districts. Most of the 

 country inhabited by it is grazing land and but thinly settled. The most 

 serious complaint against it is that it digs up the tree seeds planted on 

 timber claims on the Nebraska prairies, but this may be obviated by 

 proper care. Those living in the neighborhood of fields or where trees 

 are planted may be easily killed by any of the methods described on 

 pp. 25-27. When once killed off near the fields, others will not spread 

 over the ground for some time, usually not until the crop is beyond 

 their reach. 



RICHARDSON'S SPERMOPHILE. 



Spermophilus richardsoni (Sabine). 



[Plate Ill-Map 4.] 



Description. — Richardson's Spermophile, with its short legs, tail, and ears, strongly 

 resembles a small prairie dog in general form and color. It has no distinct markings 

 or pattern of coloration ; the outer coat is composed of longer hairs covering the fur ; 

 the inner fur is soft and silky, even in August, becoming thick and beautiful in 

 autumn. The lower parts are plain buffy, becoming brighter on the shoulders and 

 sides of neck; the top of the head, cheeks, and back are grayish buffy from a mix- 

 ture of black hairs and the darker under-fur; the tail is plain buff* below, washed on 

 the upper surface with black, and bordered by lighter buff. No dark lines are visi- 

 ble in the colors of the tail, but the back is faintly marked with fine dots or wavy 

 crosslines.* 



* The only animal with which it can be confounded is S. richardsoni elegans, a 

 southern subspecies, somewhat darker colored and less buffy. Specimens from North 

 Dakota and Manitoba are the true richardsoni, while those from Wyoming and Idaho 

 are referred to elegans. At some future time it may be possible to draw an arbitrary 

 line across Montana separating the two forms. 



