MAMMALS OF THE MEXICAN BOUNDARY. 289 



Type-locality — Fort Webster, Copper Mines of the INIinibres, Grant 

 County, New Mexico, hit. 32° 47', long. 108° 4'. (Type, skin with 

 fragment of skull. No, 3151, U. S. National Museum.) 



Geografliical range. — Upper Sonoran to lower edge of Transition 

 Zone of the Elevated Tract. 



Description. — Size medium ; ears high and pointed ; tail long, and 

 rather bushy; pelage short, but silky and dense. Coloration pallid, 

 all but the median dorsal stripe being obsolete. In post-breeding 

 pelage the color above is whitish gray, finely mixed with blackish 

 and vinaceous; dorsal stripes faintly outlined; sides, and anterior 

 portion of limbs, yellowish brown; ventral surface soiled white, 

 the fur plumbeous at base. Side of head, with three dark and two 

 white longitudinal stripes, the middle dark one involving the eye. 

 Post-auricular jDatcli large and Avhite. Ear whitish, with anterior 

 border rusty brownish, this pattern being reversed on its inner sur- 

 face. Tail broad and bushy, iron-gray above, and longitudinally 

 striped below, where the central area is orange-rufous, bordered on 

 each side, successively, with buH', black, and gi'ay, giving a 7-striped 

 pattern. Hands soiled white ; feet buff. Mammse, 4 pairs. 



The winter pelage is, of course, grayer, the upper surface lacking 

 the vinaceous tint, the subterminal zone of the underfur being nar- 

 rower, paler, and more yellowish. 



Measurements. — Average of ten adult males: Length, 231 mm.; tail 

 to end of vertebra?, 103 ; tail to end of hairs, 131 ; hind foot, 34.8 ; ear 

 from crown, 15.9; ear from notch, 21.0; head, 40.3; distance from 

 nose to eye, IG; nose to ear, 32. Average of fifteen adult females: 

 Length, 238 nmi. ; tail to end of vertebra\ 104; tail to end of hairs, 

 134; hind foot, 34.G; ear from crown, 1G.2; ear from notch, 21.2; 

 head, 40.G; distance from nose to eye, 1G.2; nose to ear, 32.3. Skull, 

 3i) l)y 21. 



Skull and teeth. — Skull (fig. 47) similar to that of Eutamias cin- 

 ercicollis, but with braincase longer and lower, and the slvull narrower 

 anteriorly; incisors broader. 



Life history. — The Gila chipmunk, as its name implies, is an in- 

 habitant of the Gila Basin; but its range is not restricted thereto, 

 and may also be found to cover a considerable portion of the Colorado 

 and Yaqui River basins. Its preference seems to l)e for l)roken, 

 rocky country, where there is timber; yet it inhabits long reaches of 

 barren canyons, entirely destitute of trees. It must, necessarily, be 

 able to subsist on a great variety of food, else it could not exist inider 

 such diverse conditions. Although quite abundant, in suitable locali- 

 ties, in the pine zone, it is more characteristic of the jagged canyons, 

 rocky basins, and precipitous slopes bordering the mesas, which con- 

 stitute such marked topographical features of this region, and which 

 30639— No. .5(;— 07 m 19 



