MAMMALS OF THE MEXiCAK BOUNDARY. 251 



Remurls. — The seasonal changes in the coating of the ears corre- 

 spond so closely with those described in the common squirrel of Eng- 

 land, by Mr. Oldfield Thomas," that I can not forbear quoting his 

 remarks : 



The hairs of the ear tufts follow very much in their changes those of the 

 tail. The terminal hairs of the ear tip belonging, like the brush hairs, to the 

 autumnal coat, lengthen and become noticeable in September, attaining their 

 maximum about January. Like the tail hairs, they steadily bleach all the time 

 from their original dark-br<Jwn color, and get white, thin, and poor in May and 

 June. In most specimens they have altogether disappeared l)y July, although 

 in rare cases a few straggling white hairs may remain in position even up to 

 the' time that in September the tips of the new tufts begin to show themselves. 

 When tufts of fair size do persist into August, their pure white color renders 

 them very striking objects. Such hairs as may grow on the ear tips at the time 

 of the spring body molt only become visible on the fall of the long tufts, and 

 always remain quite short. The short hairs may in fact be compared to the 

 aborted summer tail covering, already referred to, just as the long tufts of the 

 autumn suit correspond to the autumn brush hairs of the tail. 



The chickarees have short ear-tufts in winter, but the Abert pine 

 squirrel is the only one of our species which has these appendages 

 developed to the same extent as the squirrel of England. In this 

 species the ear-tufts fade in summer to brown instead of white. 



Life history. — The Abert pine squirrel, on account of its resemblance 

 to the typical Sciuri of the Old World, is doubtless of Asiatic origin, 

 like the chipmunks of the genus Eutamias. In the United States it 

 is known only from Arizona, New Mexico, and Colorado, being an 

 inhabitant of the southern Rocky Mountains and of the isolated 

 mountains which rise from the Colorado plateau in Arizona and New 

 Mexico. Along the Mexican line the most careful search failed to 

 discover its presence, though Dr. J. A. Allen has recorded its cap- 

 ture on the upper Bavispee River, in northern Mexico, by the mem- 

 bers of the Lumholtz Archaeological Expedition, 1890-1892, and Mr. 

 Oldfield Thomas has named the subspecies durangi^' from Durango, 

 in central Mexico. 



Its habitat is restricted to those portions of this area which are 

 covered by coniferous forests. In Arizona it is confined to the belt of 

 pine timber, for the most part included between the altitudes of 5,000 

 and 8,000 feet. 



This handsome squirrel was first described in the Proceedings 

 of the Philadelphia Academy of Natural Sciences in 1852 by Dr. 

 S. W. Woodhouse, who accompanied Captain Sitgreaves on the 

 exploration of the Zufii and Colorado rivers and obtained specimens 

 in the San Francisco Mountain, then included in the Territory 

 known as New Mexico, at present in Arizona. 



a The Zoologist, 3d ser., XX, November, 1896, p. 404. 



» 8ciurus aberti durangi Thomas, Annals and Magazine of Natural History, 

 6th ser., XI, January, 1893, pp. 49, 50. 



