In preparing maps showing the geographic distribution of North American
microtines, conflicting statements in the literature and identifications
that, if accepted, would result in improbable geographic ranges have
led to the examination of pertinent specimens with the results given
below. The studies here reported upon were aided by a contract between
the Office of Naval Research, Department of the Navy, and the
University of Kansas (Nr 161-791), by funds provided by the University
of Kansas from its Research Appropriation, and by grants for
out-of-state field work from the Kansas University Endowment
Association. Grateful acknowledgment is made to persons in charge of
the collections at each of the following institutions for permission to
use the collections under their charge: Biological Surveys Collection,
United States National Museum (herein abbreviated USBS); California
Museum of Vertebrate Zoology (MVZ); Chicago Natural History Museum
(CNHM); University of Kansas Museum of Natural History (KU); Museum of
Comparative Zoology (MCZ); United States National Museum (USNM);
Department of Economic Zoology, University of Wisconsin (UWDEZ); and
Zoological Museum, University of Wisconsin (UWZM).