In the synonymy of each subspecies there appears, first the first usage of a name, second the first usage of the name combination now employed, and third, pure synonyms.
A total of 757 specimens of chipmunks are listed as examined in the course of preparing this report. Additional specimens were less carefully examined in the Biological Surveys Collection in Washington, D.C. Specimens used in my study, unless otherwise specified, are in the Museum of Natural History, University of Kansas. The symbols representing the collections containing specimens studied are as follows:
BS—United States Biological Surveys Collection.
FC—Collection of James S. Findley.
MM—Museum of Zoology, University of Michigan.
NM—United States National Museum.
KU—Museum of Natural History, University of Kansas.
I am grateful to Professor E. Raymond Hall for guidance in my study and thank Doctors Robert W. Wilson, E. Lendell Cockrum, Keith R. Kelson, A. Byron Leonard, Rollin H. Baker, and others at the Museum of Natural History and Department of Zoology, University of Kansas, for encouragement and advice. My wife, Alice M. White, made the illustrations and helped me in many ways.
For permission to borrow and to study specimens, I thank Dr. W. H. Burt of the Museum of Zoology, University of Michigan, Miss Viola S. Schantz of the United States Fish and Wildlife Service, Mr. Colin C. Sanborn of the Chicago Natural History Museum, and Mr. James S. Findley.
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.
Secondary sexual variation in chipmunks is small; the females are slightly larger than the males. This difference in size is so slight that it can be ignored when making taxonomic comparisons, for, large samples of males and females of like age and from the same locality were compared and were found statistically not to be significantly different. This is in agreement with Johnson (1943:70) and Hall (1946:329).
Variations of taxonomic worth are treated in the accounts of species and subspecies.
Individual variation is slight, for, the analyses of measurements of the skulls of series of specimens of like age, reveal markedly low coefficients of variability resembling those published by Larrison (1949).