Type.—Female, adult, skull and skin, No. 20050 Mus. Nat. Hist., Univ.
Kansas; from 3 mi. NW Sundance, 5900 ft., Crook County, Wyoming; obtained
on July 4, 1947, by H. W. Setzer; original No. 1692.

Range.—Bear Lodge Mountains in northeastern Wyoming and the Black
Hills of South Dakota.

Diagnosis.—Size large (see measurements); general tone of upper parts drab;
sides Ochraceous Buff (capitalized terms are of Ridgway, Color Standards and
Color Nomenclature, Washington, D. C., 1912); lateral stripes Fuscus Black
washed with Ochraceous Tawny; ventral side of tail near (14' h) Ochraceous
Orange and fringed with black.

Comparisons.—From Eutamias minimus pallidus (specimens from Buffalo in
Johnson County, Ivy Creek, Rockypoint, Middle Butte, and South Butte in
Campbell County, all in Wyoming, and Harrison, Sioux County, Nebraska),
the subspecies to the southward, westward, and northward, E. m. silvaticus
differs in: General tone of upper parts markedly darker, more reddish and less
grayish; dorsal stripes darker; crown markedly darker. External measurements,
and measurements and characters of the skull of the two subspecies, do not
differ significantly. Unless otherwise specified all comparative material is in the
Museum of Natural History of the University of Kansas.

From Eutamias minimus cacodemus (topotypes in the United States National
Museum), the subspecies to the southeastward, E. m. silvaticus differs in the
same manner in which it differs from E. m. pallidus, but the degree of difference
is greater because E. m. cacodemus is even paler than E. m. pallidus.

From Eutamias minimus confinis (specimens from 17½ mi. E and 4½ mi. S
Shell, 8500 ft., Big Horn County, Wyoming), E. m. silvaticus differs in: General
tone of upper parts darker, more reddish and less grayish; sides of rump
more reddish and less grayish; underside of tail more tawny; skull distinctly
longer and broader across zygomata.

From Eutamias minimus borealis (specimens from 1 mi. NW of junction of
Irons Creek and Laird River; N side Muskwa River, 4 mi. W Ft. Nelson, 1200
[Pg 262]ft.; E side Minaker River, 1 mi. W Trutch; Beatton River, 115 mi. S Ft. Nelson;
5 mi. W and 3 mi. N Ft. St. John; S side Toad River, 10 mi. S and 21 mi. E
Muncho Lake; all in British Columbia; and from Assineau River, 1920 ft.,
10 mi. E and 1 mi. N Kinuso, Alberta), E. m. silvaticus differs in: Under side
of tail more reddish; dorsal stripes less blackish; sides slightly paler (less tawny);
nasals distinctly shorter; skull distinctly shorter.

Measurements.—Average and extreme measurements of three adult males
and 11 adult females of E. m. silvaticus from the type locality are, respectively,
as follows: Total length, 190 (189-190), 207 (202-220); length of tail, 85 (81-90),
97 (82-105); length of hind foot, 31 (30-33), 32 (31-34); length of ear,
14 (13-16), 15 (14-17); weight, 45.7 (44.6-46.5), 55.7 (50.0-68.0); greatest
length of skull, 32.0 (31.5-32.6), 32.3 (31.5-33.1); zygomatic breadth, 18.5
(18.5-18.5), 18.6 (18.2-19.0); least interorbital constriction, 6.9 (6.8-7.1), 7.0
(6.4-8.1); length of nasals, 9.4 (9.2-9.6), 9.6 (9.3-10.1).

Measurements of the type.—Total length, 206; length of tail, 90; length of
hind foot, 32; length of ear, 15; weight, 59.3; greatest length of skull, 32.6;
zygomatic breadth, 18.6; least interorbital constriction, 6.4; length of nasals, 9.3.

Specimens examined.—Total number, 28. Specimens from South Dakota
are in the United States National Museum, and those from Wyoming are in the
Museum of Natural History of the University of Kansas.

South Dakota: Custer Co.: Custer, 3; Lawrence Co.: Deadwood, 10.

Wyoming: Crook County: 3 mi. NW Sundance, 5900 ft., 14; 15 mi. ENE
Sundance, 3825 ft., 1.

Acknowledgment is made of assistance, with the field work, received from
the Kansas University Endowment Association.

Museum of Natural History, University of Kansas, Transmitted December 8,
1951.