320 BULLETIN T), UNITED STATES NATIONAL MUSEUM. 



near Foit Verde (altitude about 5,500 feet); while 3'oung no larger 

 than the eastern red squirrel were taken in the Verde River bottom, 

 2,000 feet lower, two months later; and a female, shot near Fort 

 Verde on June 14, contained five small fetuses. 



The normal individual variation in color is considerable in this spe- 

 cies. This variation consists in the relative preponderance of shades 

 of gra}^, brown and fulvous al)ovc, and in the color of the under sur- 

 face, Avliich varies from soiled white to brown. Examples from the 

 Verde Valley, taken early in June, had shed their coats on the front 

 half of the bt)dy, the after parts remaining long haired and of a dif- 

 ferent color from the front half. Their tails were very scantil}^ haired 

 at that season. Slightly" melanistic examples were occasionall}" seen; 

 and a i)erfect albino, having colorless claws and pink e3^es, was taken 

 alive at Whipple Barracks, Arizona, on September 20, 1887. The 

 latter was a young of the year and died soon after its capture. Males 

 were sometimes taken, though rarely, in which the testicles were 

 abdominal; and, in one specimen, they were wholly absent. 



On the United States and Mexican Boundary line this rock-squirrel 

 is found in rocky places in the Eastern Desert Tract. Some were seen 

 at El Paso early in November, 1892. Several were seen at the Upper 

 Corner (Monument No. 40), April and May, 1892. One was shot on 

 the actual suunuit of Hachita Grande, altitude 2,515 meters or 8,350 

 feet. Thence westward it was seen in abundance, except in cold 

 weather, to La Osa (Monument No. 110). It was especialh' abundant 

 in the oak forests of the San Luis and Patagonia mountains, and was 

 sometimes utilized as food b}'^ members of the Surve}'. We saw none 

 while camped at Pozo de Luis, Sonora, from December 29, 1893, to 

 Januar}" 8, 1891, but ""squirrels" were seen farther west, at Nariz 

 Mountain, b}^ several members of the party, which may have been this 

 species or AinriiosjJcDnojyhthis harrUil. 



In the Dog Mountains one was shot on Emory Peak, and the skin 

 was made into a purse by "" Bob," an Apache Indian trailer. Although 

 this species was abundant, no form of Kutamias. or AminoH])erinophilus 

 was found to inhabit the Dog Mountains. 



It was common from the lower timber line to the summit (2,498 

 meters or 8,196 feet) of the San Luis Range, where it often climbed 

 the tallest oaks for acorns, upon which it loves to feed. A female con- 

 tained 7 small fetuses, June 23, 1892, and young, from half to two- 

 thirds grown, were taken at the end of September; quite young ones, 

 July 18. 



I found it exceedingly numerous on the upper forks of Cajon Bonito 

 Creek in September, 1893. It uttered a startling succession of loudly 

 whistled notes in descending scale and single loud whistles. It was 

 unusualh'^ active after rain. It was feeding on mallow, walnut, and 

 oak mast. It often burrowed into the enormous piles of driftage 



