Diagnosis.—Size medium; sides dark; general tone of upper parts dark; dorsal light and dark stripes strongly contrasting.
Description.—Color pattern: Head Cinnamon mixed with grayish white; stripe on margin of crown Verona-Brown or Bister; ocular stripe Fuscous Black mixed with Sayal Brown; submalar stripe Sayal Brown; ear Fuscous, Sayal Brown along anterior margin and Smoke Gray along posterior margin and on postauricular patch; median dorsal stripe black; lateral dorsal dark stripes Fuscous Black mixed with Russet; outermost dorsal dark stripes slightly darker or indistinguishable from sides in color; dorsal light stripes grayish white with Mikado-Brown along margins; outermost pair of dorsal light stripes nearly pure white; sides Russet mixed with Cinnamon or Ochraceous-Tawny; rump and thighs Smoke Gray mixed with Cinnamon-Buff, with a larger or smaller number of Fuscous Black hairs; antipalmar and antiplantar surfaces of feet Cinnamon-Buff; dorsal surface of tail black; ventral surface of tail Sayal Brown to Tawny; underparts white with dark underfur. Skull and Baculum: As in E. u. umbrinus.
Comparisons.—From E. u. inyoensis, the subspecies to the west, E. u. adsitus differs in: General tone of upper parts darker; sides darker; interorbital region wider; skull significantly deeper.
For comparison with E. u. umbrinus, E. u. sedulus, and E. u. montanus, see the accounts of those subspecies.
Remarks.—Specimens from West Rim, Zion National Park, 6,500 ft., Washington County, Utah, seem to be intergrades between E. u. adsitus and E. u. inyoensis, and are referable to E. u. adsitus.
Specimens examined.—Total number, 34.
Utah: Beaver Co.: Britts Meadow, Beaver Range Mountains, 8,500 ft., 13 BS. Wayne Co.: Donkey Lake, Boulder Mountain, 10,000 ft., 4 UU. Garfield Co.: Wildcat R. S., Boulder Mountain, 8,700 ft., 5 UU.
Arizona: Coconino Co.: De Motte Park, Kaibab Plateau, 3 BS; Bright Angel, Kaibab Plateau, 9 BS.
Eutamias umbrinus sedulus new subspecies