The differences in anatomy and color between many species of chipmunksare subtle, and refined techniques are required to discover them. When"measuring" chipmunks taxonomically, it is necessary to use a"chipmunk scale" and not, for example, a "pocket-gopher scale." Inexplanation, some species of pocket gophers closely allied to eachother, and even some subspecies of the same species, differ markedlyin color and in size and shape of parts of the skeleton; comparabledifferences are not so pronounced among many species of chipmunks.
Merriam (1905) was the first to show clearly that Eutamiasquadrivittatus is a distinct species, and pointed out that E. amoenusoperarius (= 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. quadrivittatusas 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. quadrivittatushave been: E. q. quadrivittatus, E. q. hopiensis, E. q. inyoensis,E. q. nevadensis, E. q. umbrinus, and E. q. adsitus.
Capitalized color terms, which are used in descriptions andcomparisons, 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 aname, second the first usage of the name combination now employed unless anew combination is proposed by me, and third pure synonyms. The last isrecognizable as such because the type locality is appended to each.
Unless otherwise specified, all specimens are in the Museum of NaturalHistory, University of Kansas. The various collections of institutionsand 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