Description.—Color pattern: Crown Sayal Brown washed with Cinnamon-Buff; facial stripes Fuscous Black mixed with Clay Color; anterior margin of ear Ochraceous-Orange; hairs inside posterior part of pinna Ochraceous-Buff; posterior margin of ear and postauricular patch grayish white; dorsal dark stripes Fuscous Black more or less mixed with Ochraceous-Buff; medial dorsal light stripes Pale Smoke Gray with Ochraceous-Buff along margins; lateral dorsal light stripes grayish white or white with Ochraceous-Buff along margins; sides Ochraceous-Buff; rump and thighs Smoke Gray washed with Ochraceous-Buff; dorsal surface of tail black interspersed with Ochraceous-Buff; ventral surface of tail Ochraceous-Orange, with black along margin and Light Ochraceous-Buff along outermost edge; antipalmar and antiplantar surfaces of feet Light Buff; underparts creamy white sometimes washed with Ochraceous-Buff. Skull and Baculum: Large but of same proportions as in other subspecies of E. minimus.
Comparisons.—From E. m. operarius, the subspecies from south-central Wyoming, E. m. silvaticus differs in: Underside of tail lighter; general tone of upper parts grayer; sides lighter; skull and baculum of same size and proportions.
For comparisons with E. m. pallidus and E. m. confinis, see the accounts of those subspecies.
Remarks.—Intergradation between E. m. silvaticus and E. m. pallidus has already been discussed under the account of E. m. pallidus.
Specimens examined.—Total number, 42.
Crook Co.: 15 mi. N Sundance, Black Hills Nat. Forest, 5,500 ft., 6; 15 mi. ENE Sundance, 3,825 ft., 1; 3 mi. NW Sundance, 5,900 ft., 14; 1 mi. N Sundance, Black Hills Nat. Forest, 1.
Weston Co.: 1½ mi. E Buckhorn, 6,150 ft., 19; SE Newcastle, 1 (MM).
Additional records (Howell 1929:57): Crook Co.: Devils Tower; Sundance.
[ Eutamias minimus operarius Merriam ]
Eutamias amoenus operarius Merriam, Proc. Biol. Soc. Washington, 18:164, June 29, 1905.