222 BULLETIN 56, UNITED STATES NATIONAL MUSEUM. 



centic area above, and a white shield-shaped area below. The fawn 

 color occupies the back and most of the neck, extending down the 

 outer side of the limbs and encircling them low down, and back- 

 ward in a narrow line, dividing the rump and ending on the upper 

 side of the tail. This color becomes more tawny on the neck, and 

 the elongated hairs forming the main are russet, tipped with black. 

 The upper side of the head, which varies from creamy white on the 

 ?ides to wood brown or even tawny-fawn color, above, is strongly 

 marked with brownish black in the male, and there are whitish areas 

 around the horns and at the base of the ears. The black markings are 

 much more extensive in old males than in young or female individuals. 

 In old bucks of Antilocapra americana americana the black sometimes 

 occupies the whole face in front of a line connecting the horns, but, 

 in most cases, an oval fawn-colored space is inclosed. In Antilocapra 

 americana mexicana the black becomes dark brown and only occupies 

 the end of the muzzle and a narrow space in front of the horns, much 

 as in northern females, leaving the middle of the upper side of the 

 head wood brown. In both forms the eyelashes are jet- black, and 

 there is a black listing on the edges of the ear, apically, and a black 

 spot — in the male^occupying the side of the head below the angle 

 of the ja-w; the latter a sex mark serving to distinguish between the 

 sexes at all ages, even in some fetal specimens. In americana the 

 tail appears to be white, except for a tawny basal area on its upper 

 side, but in mexicana the sides of the tail are grayish drab. 



Variations in color. — Considerable color differences are dependent 

 upon season, sex, and age. An adult male (No. 440, Mearns's collec- 

 tion), killed in the MogoUon Mountains, 25 miles northeast of Fort 

 Verde, central Arizona, August 2, 1886, is in full summer pelage. 



The face has a jet-black area, beginning at the nares, which it in- 

 volves, passing backward to the horns, where it ends abruptly, ex- 

 tending laterally to the orbits. On the forehead, in the middle of 

 this black area, are a few light hairs. Upon the sides of the head 

 below the ears is another large black patch, which shades off to red- 

 dish fulvous and white. The cheeks, space between horns and around 

 base of ears, and the lips are pure white or whitish. Below the white 

 cheeks and black forehead are patches of pale fawn color. The ears, 

 which resemble those of the horse, are very acutely pointed, straight- 

 edged for basal two-thirds anteriorly, then sinuously curved — at 

 first concave and then convex on border — to the tip, which points 

 toward the horn, and regularly rounded on the posterior border; 

 convexity of ear pale fulvous ; its terminal portion edged with black ; 

 its extremity tipped with black, somewhat mixed with fulvous, on 

 both surfaces; inner surface of ear white, except at one point, where 

 the fulvous extends over upon the posterior border from the outside. 



Adult male (No. 379, Mearns's collection), killed in the MogoUon 



