Variation of selected taxonomic characteristics of flat-headed snakes
(_Tantilla gracilis_ Baird and Girard) from several midwestern states
was studied by Force (1935), but she did not attempt a comprehensive
evaluation. Taylor (1936) reported on variation in _T. gracilis_ from
various localities in Kansas; Kirn, Burger, and Smith (1949) studied
selected structures of specimens of _T. gracilis_ from throughout its
range. The present study was undertaken to determine the variation in
both currently used and potential taxonomic characteristics of _T.
gracilis_ from one locality.
We are thankful to Charles W. Myers, Gorgas Memorial Laboratory, for
suggestions concerning characteristics examined. We are indebted to Drs.
William G. Degenhardt, University of New Mexico, Herndon G. Dowling, New
York Zoological Society, Charles H. Lowe, University of Arizona, and
Richard G. Zweifel, American Museum of Natural History, for criticizing
the manuscript. Dr. William E. Duellman permitted us to study specimens
in the University of Kansas Museum of Natural History.