_Description._--_Color pattern_: Crown Cinnamon mixed with Smoke Gray; upper two facial stripes black; submalar stripe Fuscous or Fuscous Black mixed with Ochraceous Tawny; anterior margin of ear Ochraceous Tawny; posterior margin of ear and postauricular patch Light Buff or buffy white; hairs inside posterior part of pinna Ochraceous Tawny; median dorsal dark stripe black; lateral pair of dorsal dark stripes black and mixed with Tawny, frequently brownish; median pair of dorsal light stripes white tinged with Pale Smoke Gray; lateral pair of dorsal light stripes creamy white; sides Tawny or Ochraceous Tawny; rump and thighs Dark Smoke Gray strongly mixed with Cinnamon Buff; dorsal surface of tail Fuscous Black mixed with Clay Color; ventral surface of tail Light Ochraceous Tawny, with Fuscous Black around margin and Clay Color around outermost edge; antipalmar and antiplantar surfaces of feet Cinnamon or Cinnamon Buff; underparts Cinnamon Buff or Light Ochraceous Buff. _Skull_: Size medium; moderately narrowed across zygomata. _Baculum_: Slender; not noticeably broadened at base; tip more than 30 per cent of length of shaft. _Remarks._--Although there are no records of this subspecies from the Wind River Mountains, it probably occurs there. The niche that this subspecies occupies is similar to that of _E. m. consobrinus_ as shown by the fact that these two subspecies have been taken together at the same places. Specimens of _E. a. luteiventris_ and _E. umbrinus fremonti_ have been taken together at the same places. In general, _E. m. consobrinus_ occurs in open country and at the edges of forests, whereas _E. u. fremonti_ occurs in the forest. _E. a. luteiventris_ occurs in the intermediate habitat, that is to say, not far into the forest, and not so far out into the open as _E. m. consobrinus_. _Specimens examined._--Total number, 83. _Yellowstone Park_: Unspecified, 2. _Park Co._: 31-1/2 mi. N and 36 mi. W Cody, 6,900 ft., 6; 29 mi. N and 31 mi. W Cody, 7,200 ft., 1; 28 mi. N and 30 mi. W Cody, 7,200 ft., 1; 16-1/4 mi. N and 17 mi. W Cody, 5,625 ft., 3; 25 mi. S and 28 mi. W Cody, 6,350 ft., 2.