342 bulletin: museum of comparative ztoology. 



'pinkish buff,' the hairs paUng on their middle third and darkening by 

 imperceptible degrees to gray or slate gray at their extreme bases. 

 DoAvny hairs at the posterior bases of the ears whitish. Below, the 

 general appearance is 'pale ochraceous buff,' the hairs darkening 

 gradually toward their bases to a neutral gray, except in the middle 

 region of the throat, where usually the hairs are not perceptibly darker 

 at base. 



Immature specimens have the pelage more dusky throughout than 

 the adults. The basal two thirds of the hairs above is nearly ' neutral 

 gray' with short pale tips of buffy, nearly 'vinaceous buff.' Below, 

 the color is paler, the light tips of the hairs a soiled whitish. 



Color Variation. — In a large series of skins that may fairly be taken 

 to represent pallescens, there is much individual variation in the 

 intensity of coloring among adults. A specimen from Ash Creek, 

 Graham IMts., Arizona (204375 Biol. Survey Coll.) has the basal halves 

 of the hairs 'slate color' producing an effect much darker than usual. 

 It may be considered a step in approach to the dark subspecies of the 

 Mexican highlands. Two specimens (10694, 10695 Univ. of Cali- 

 fornia Coll.) obtained by Dr. Joseph Grinnell at Riverside Mountain, 

 Colorado River, southeastern California, are the brightest colored 

 individuals I have seen, with a distinct reddish cast to the upper 

 surface, nearly 'vinaceous cinnamon,' shading into a 'buff pink' 

 below, the bases of the hairs only slightly darkened. The palest 

 specimen of all is one collected in the hills back of Lone Pine, California, 

 by Dr. Theodore Lyman's expedition of 1915. It is 'pale pinkish 

 buff' above and nearly white below to the roots of the hairs. Apart 

 from these slight variations pallescens is remarkably uniform in tint 

 over a wide range of territory. 



Shnll. — The skull of this race is hardly to be distinguished from 

 that of true megalotis. To the eye, it seems a trifle narrower across 

 the rosti-um but the difference is not clearly brought out by measure- 

 ments. The upper inner incisor is normally without the lateral 

 cusp characteristic of macrotis. 



Measurements. — No. ||-|f, Coll. Amer. Mus. Nat. Hist., from 

 Prescott, Arizona: forearm 43 mm. (average of four Arizona speci- 

 mens 42.6); digit III, metacarpal 37.3 (average of four 37.5); first 

 phalanx 13 (average of four 13); second phalanx 16 (average of four 

 17.2); tibia 18. Collector's measurements, No. 204375, Biol. Sur- 

 vey Coll., Graham Mts., Arizona, total length 1182 mm.; tail 50; 

 foot 9; extent of wings 300. 



Skull: No. 204375 Biol. Survey Coll., Graham Mts., Arizona: 



