New Squirrels from Mexico and Central America. 153 



tail, same color as nape. Ears grizzled grayish or dull rusty rufous on 

 inner side; behind rufous or rusty gray anteriorly, posteriorly covered 

 with long white fur, forming part of the conspicuous white patch behind 

 base. Eyes surrounded by rings of fulvous and whitish ; sides of nose 

 and lower part of cheeks gray, varying in intensity. Tops of fore and 

 hind feet white, shading through gray on legs to color of body. Anal 

 region and base of tail all round like adjacent part of rump. Upper sur 

 face of tail black, washed with white, the bright rufous basal color some 

 times showing through ; below a median band of deep, rich rufous with 

 scarcely a trace of dark grizzling, but bordered on each side by narrow 

 band of black, edged with white. Chin white ; sides of throat some 

 times shaded with same ; anal region gray ; rest of lower parts deep rich 

 rufous, very uniform in the series before me. 



Measurements. Type specimen : Total length 502 ; tail vertebrae 247 ; 

 hind foot 68. Average of 5 adults : Total length 496.8 ; tail vertebrae 249 ; 

 hind foot 68. 



Remarks. An old female in worn fur taken with the other specimens 

 the last of December may represent the summer pelage. The rump patch 

 is as conspicuous as the nape patch and agrees with it in color. The tops 

 of fore and hind feet are dark gray ; inside of legs dingy whitish shading 

 into the dull whitish-rufous that covers throat, breast, and abdomen ex 

 cept ring of white around mammre ; chin white. The lower surface of 

 tail is darker rufous "than body and distinctly grizzled with black. Top 

 of nose and area between nape and rump patches grizzled gray, black, 

 and rusty rufous, the gray most conspicuous. 



Among five adult winter specimens in the perfect pelage described 

 above one is darker than the others on dorsal surface, owing to an increase 

 in amount of black on tips of hairs. Another specimen has the rufous of 

 under surface extending up on sides behind fore legs and uniting with a 

 backward extension of the nuchal patch much like S. aureogaster. The 

 rest of dorsal surface is less heavily grizzled with gray than usual and 

 rusty-red predominates, so that the prevailing shade is dull rusty-red 

 thinly grizzled with grayish white. The white on tops of feet is washed 

 with reddish. Two half-grown young taken the last of December are in 

 the same pelage as the adults, agreeing with the average adults except in 

 having only the toes white and rest of feet gray. The nearest ally of this 

 subspecies appears to be typical S. albipes. The white ear patches are 

 more conspicuous than in any Mexican squirrel known to me. 



Sciurus nelsoni hirtus subsp. nov. Popocatepetl Squirrel. 



Type from Tochimilco, Puebla, Mexico. No. 55325, J ad., U. S. Nat. 

 Mus-, Biological Survey Coll. Collected Aug. 7, 1893, by E. W. Nelson 

 and E. A. Goldman. Orig. No. 5295. 



Distribution. Volcanoes of Iztaccihuatl and Popocatepetl, in States of 

 Mexico and Puebla, Mexico. 



Characters. Size of S. nelsoni, but distinguished by distinct patches of 

 dingy fulvous on nape and rump ; by iron-gray color on middle of back 



33 Bior,. Soc. WASH.. VOL. XII, 1898 



