Diagnosis.—Size medium; general tone of upper parts tawny; cranial breadth averaging between 16.0 and 16.8 mm.; baculum distinguishable from that of any other species by the combination of width of base less than ¼ of length of shaft, shaft having a maximum diameter of more than ¼ mm., and height of keel ¼ of length of tip.
Eutamias quadrivittatus quadrivittatus (Say)
Sciurus quadrivittatus Say, in Jones, Long's Expedition to Rocky Mountains, 2:45, 1823.
Eutamias quadrivittatus, Miller and Rehn, Proc. Boston Soc. Nat. Hist., 30:43, December 27, 1901.
Tamias quadrivittatus gracilis J. A. Allen, Bull. Amer. Mus. Nat. Hist., 3:99, June 1890, Type from San Pedro, Santa Fe Co., New Mexico.
Eutamias quadrivittatus animosus Warren, Proc. Biol. Soc. Washington, 22:105, June 25, 1909. Type from Irwin Ranch, Las Animas County, Colorado.
Type.—None designated; from along Arkansas River, about 26 mi. below Canon City, Fremont County, Colorado; obtained on July 18, 1820.
Diagnosis.—Size medium; dorsal dark stripes blackish; sides Cinnamon to Clay Color; crown Light Drab; baculum large.
Description.—Color pattern: Head Cinnamon, shaded on crown to Light Drab; ocular stripe Fuscous Black, with Cinnamon along margins; other facial stripes Fuscous mixed with Cinnamon; ears Fuscous Black, Ochraceous-Tawny on anterior margin, grayish white on posterior margin and on postauricular patch; dark dorsal stripes black with Ochraceous-Tawny along margins; outer pair of dark stripes often mainly Tawny; light dorsal stripes grayish white, outer pair usually creamy white; sides Ochraceous-Tawny, shaded in the region of the shoulder with Cinnamon; rump and thighs Cinnamon-Buff mixed with Smoke Gray; antipalmar surfaces of forefeet Cinnamon-Buff; antiplantar surfaces of hind feet Pinkish Buff; dorsal surface of tail Fuscous Black, overlaid with Pinkish Buff; ventral surface of tail Ochraceous-Tawny, Fuscous Black along margin, Pinkish Buff along outermost edge; underparts creamy white. Skull: Large; braincase well inflated; zygomatic arches strong and slightly appressed to skull. Baculum: Large; long and slender.
Comparisons.—From E. q. hopiensis, the only other subspecies in this species, E. q. quadrivittatus differs in: Dorsal dark stripes blackish; crown grayer; rump and thighs grayer; general tone of upper parts darker.