ines by one of us (Cockrum), and the completion of a
Master's thesis on the geographical variation of the red-backed mice
of Wyoming by the other (Fitch) we had occasion to study the
red-backed mice of the southern Rocky Mountain region (see figure 1).
Results of these studies are the recognition of two heretofore unnamed
subspecies of the red-backed mouse in the southern Rocky Mountain
region, and a clarification of the taxonomic status of two additional
kinds.

+Clethrionomys gapperi galei+ (Merriam)

1890. _Evotomys galei_ Merriam, N. Amer. Fauna, 4:23, October 8.

1931. _Clethrionomys gapperi galei_, Hall, Univ. California Publ.
Zool., 37:6, April 10.

1897. _Evotomys gapperi galei_, Bailey, Proc. Biol. Soc. Washington,
11:126, May 13.

_Type locality._--Ward, 9500 feet, Boulder County, Colorado.

_Range._--The Rocky Mountains of extreme southern Alberta, Montana,
northwestern and southern Wyoming, and north and central Colorado.

_Remarks._--_C. g. galei_, with the largest geographic range of any
of the Rocky Mountain subspecies, is also the most variable. Three
principal areas of geographic variation were found. These areas are:
The mountains of north-central Colorado and southern Wyoming (this
area includes the type locality); the Big Horn area probably northwest
into Montana (no adult specimens from Montana or Alberta examined);
and the Teton area which includes the mountains east and southeast of
Yellowstone National Park. Specimens from these areas have noticeable
differences in pelage, but no constant cranial differentiation could
be detected. Specimens from the Medicine Bow Mountains of southern
Wyoming have a more reddish dorsal stripe, and more buff and less gray
on the sides than either of the northern geographic variants. The
dorsal stripe continues farther anteriorly and is better defined
through its entire length. There are fewer differences between the two
northern geographic variants than between either one of them and the
southern variant. Specimens from the Teton Mountains, however, have
grayer sides, and the outer margin of the ear is tipped with chestnut
(little or no chestnut shows on the ears of the specimens from the Big
Horn Mountains); the dorsal stripe is less distinct (with slightly
more gray throughout) than in either of the other geographic variants
of the one subspecies.

Three specimens (two adults) are available from the Little Medicine
Range in Converse County (22