ed to each
other, and even some subspecies of the same species, differ markedly
in color and in size and shape of parts of the skeleton; comparable
differences are not so pronounced among many species of chipmunks.

HISTORICAL SUMMARY

Merriam (1905) was the first to show clearly that _Eutamias
quadrivittatus_ is a distinct species, and pointed out that _E.
amoenus operarius_ (= _E. minimus operarius_) is a small species
which resembles, and is found in some areas together with, _E.
quadrivittatus_.

Howell (1929) placed under _E. quadrivittatus_ the following
subspecies: _E. q. quadrivittatus_, _E. q. hopiensis_, _E. q.
inyoensis_, _E. q. frater_, _E. q. sequoiensis_, and _E. q.
speciosus_.

Hardy (1945) placed _E. adsitus_ under _E. quadrivittatus_ as _E. q.
adsitus_, and Kelson (1951) placed _E. umbrinus_ under _E.
quadrivittatus_ as _E. q. umbrinus_.

Johnson (1943) re-established _E. speciosus_ as a separate species,
and in California left only _E. q. inyoensis_ in _E. quadrivittatus_.

Thus, since 1943 the recognized subspecies of _E. quadrivittatus_ have
been: _E. q. quadrivittatus_, _E. q. hopiensis_, _E. q. inyoensis_,
_E. q. nevadensis_, _E. q. umbrinus_, and _E. q. adsitus_.

METHODS, MATERIALS, AND ACKNOWLEDGMENTS

Capitalized color terms, which are used in descriptions and
comparisons, are of Ridgway, "Color Standards and Color
Nomenclature," Washington, D. C., 1912.

In the synonymy of each subspecies there appears only the
first usage of a name, second the first usage of the name
combination now employed unless a new combination is proposed
by me, and third pure synonyms. The last is recognizable as
such because the type locality is appended to each.

Unless otherwise specified, all specimens are in the Museum
of Natural History, University of Kansas. The various
collections of institutions and of private persons are
indicated by the following symbols:

AM--American Museum of Natural History.
BS--United States Biological Surveys Collection.
CM--Colorado Museum of Natural History.
DC--Collection of Donald R. Dickey (now the collection of the
University of California at Los Angeles).
FC--Collection of James S. Findley.
KU--Museum of Natural History, University of Kansas.
MM--Museum of Zoology, University of Michigan.
NM--United States National Museum.