r> i s 



MONOGRAmS OF NORTH AMERICAN RODBNTIA. 



of the upper parts, and pure, being not mixed with any dusky, and the color 

 extending to the roots of the hairs. The entire under pails, including the 

 whole lore leg, the hind feet, and inner side of hind leg, are snowy white, 

 the hairs having no basal color. The tail is obscurely bicolor, white below, 

 and not very sharply colored above to correspond with the areas of the body. 



Very young specimens, though nearly full grown and showing a sharp 

 lateral streak, are more simply colored above than the adults, being grayish, 

 with extremely faint huffy lining, instead of sharply blackish and buff. There 

 is also observable, in the series before me, a tendency to exhibit two differ- 

 ent tones of coloration. Those from dry regions east of the mountains arc 

 mixed grayish-brown and grayish-buff, with the lateral pale buff stripe not 

 very conspicuous. In New Mexico, Southern Texas, and southward, the ani- 

 mal frequently assumes a ruddier shade of the light color, mixed with much 

 less blackish ; in these, the lateral stripe is quite indistinct, because the upper 

 parts in general are not very different. But the distinctions in these cases 

 are not strong enough to require anything further than this notice of the fact. 



The following table of measurements will illustrate the size and shape 

 of the species very fairly, and to some extent expose the range of variation : — 



Table IV. — Measurements of eighteen specimens of Ckicetodipus flavus. 



