Nelson Descriptions of New Squirrels from Mexico. 149 



Zonal distribution. Arid tropical. 



Subspecific characters. Most like Sciurus p. nemoralis, but upperparts 

 paler or lighter gray, nuchal patch more clearly defined yellowish ; rump 

 patch more obsolescent. 



Description of type. Top of head iron-gray; nape patch ochraceous 

 mixed with black ; rest of back pale grizzled gray with slight mixture of 

 ochraceous grizzling posteriorly, but not sufficient to form a rump patch ; 

 sides of body paler than back ; top of tail black with heavy wash of white ; 

 tops of feet white; underparts of body white; median area on underside 

 of tail dull gray bordered with blackish ; outer edge of tail white. 



Measurements oflype. Total length, 543 ; tail vertebrae, 275 ; hind foot, 69. 



Skull characters Rostrum heavier and braincase narrower than in S. p. 

 nemoralis, with braincase more abruptly constricted posteriorly and occipi 

 tal diameter shorter. 



General notes. Compared with a similar series of typical S. p. nemoralis 

 (the most closely allied form) the present subspecies is distinctly lighter 

 colored, the yellowish nape patch averages decidedly better denned, and 

 the rump patch is scarcely or not at all appreciable in most specimens and 

 poorly defined when present. In all except melanistic specimens the pale 

 grayish wash on the back and sides is underlaid with buffy or yellowish 

 similar in shade to the nape patch and varying in amount so that in some 

 specimens it is scarcely distinguishable, but it usually shows through the 

 overlying gray sufficiently to give a pale yellowish suffusion. As might be 

 supposed from the climatic differences the tail is decidedly slenderer or 

 less bushy than in nemoralis and the pelage much thinner and shorter 

 haired. Melanism sometimes occurs in this form, as attested by one 

 specimen taken. 



Sciurus poliopus perigrinator subsp. nov. 



PUEBLA SQUIRREL. 



Type No. 70,279, adult female, U. S. National Museum, Biological Survey 

 Collection. From Piaxtla, Puebla, Mexico. Collected November 25, 1894, 

 by E. W. Nelson and E. A. Goldman. Original No. 7104. 



Geographic distribution. Southern Puebla, northwestern Oaxaca and ad 

 jacent parts of Guerrero. 



Zonal distribution. From upper Sonoran to arid tropical. 



Subspecific characters. Most like Sciurus p. hernandezi but more brightly 

 colored ; rump and nape patches well marked ; underside of tail rusty red 

 almost as in typical poliopus. 



Description of type. Top of nose and fore part of crown iron-gray ; back 

 part of crown and nape marked with a dark ochraceous buffy patch 

 mixed with black ; rest of upperparts to rump light iron-gray, underlaid and 

 mixed with ochraceous; sides of body paler than back; rump with a 

 distinct ochraceous patch mixed with black ; tops of feet white ; upper- 

 side of tail black with a strong wash of white and underlaid basal ly with 

 rusty ochraceous; underparts of body rich cream-buff; underside of tail 



