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.
UU--Museum of Zoology, University of Utah.
WC--Collection of Edward R. Warren, Colorado College.
Of the external measurements, only the total length and
the length of the tail are recorded in table 1. Some field
collectors measured the ear from the notch and others from
the crown; most collectors measured the length of the hind
foot to the nearest millimeter rather than in tenths of a
millimeter, as would have been desired. Consequently, I
decided against using the lengths of the ear and hind foot in
the study here reported on.
The measurements of the skull were made as shown in figure 1.
[Illustration: FIG. 1. Dorsal view of skull and a lateral and
a medial view of the right lower jaw to show points between
which measurements of the skull were taken. x 1-3/4. Based on
_Eutamias ruficaudus ruficaudus_, from 6 mi. S St. Mary, 6500
ft., Glacier Co., Montana. A to A'--greatest length of skull;
B to B'--length of nasals; C to C'--zygomatic breadth; D to
D'--least interorbital constriction; E to E'--cranial
breadth; F to F'--inner mandibular length; G to
G'--condylo-alveolar length of mandible.]
A total number of 434 specimens are listed as examined in
this study, and additionally, numerous other specimens were
superficially examined in the United States Biological
Surveys Collection. Bacula of each of the named kinds of
chipmunks in this paper, were examined.
Whenever two or more samples are stated to be significantly
different, the meaning is that the difference is
statistically significant.
The geographic distribution of each subspecies and the
localities of specimens or series of specimens are plotted on
the map (fig. 2).
When comparisons were made to ascertain specific and
subspecific differences, only adults, or animals in which the
enamel was worn through on the permanent P4 and p4 were used.
Within this age range, only specimens in comparable pelage
were used to ascertain differences in color.
Miss Viola S. Schantz of the United States Fish and Wildlife
Service, Mr. Alfred Bailey of the Colorado Museum of Natural
History, Dr. W. H. Burt of the Museum of Zoology of the
University of Michigan, Dr. Stephen D. Durrant of the Museum
of Zoology of the University of Utah, Dr. Robert M. Stabler,
curator of the Warren Collection of Colorado College, and Mr.
James S. Findley, generously loaned specimens for my use.
Doctors E. Raymond Hall, Rollin H. Baker, Robert W. Wilson,
Keith R. Kelson, E. Lendell Cockrum, and other friends and
associates have given valued suggestions and assistance. My
wife, Alice M. White, made the illustrations and helped me
record and analyze the data.
Assistance with field work is acknowledged from the Kansas
University Endowment Association, the National Science
Foundation, and the United States Navy, Office of Naval
Research, through contract No. NR161 791.