Position of the Supraorbital Notch 554
Degree of Convergence of the Upper Tooth-rows 554
Degree of Constriction of the Interorbital Region 555
Shape of the Pinna 555
Structural Features that are too Weakly Expressed
to be of Taxonomic Use 555
Discussion 555
Genera and Subgenera 557
Genus _Eutamias_ Trouessart 557
Subgenus _Eutamias_ Trouessart 558
Subgenus _Neotamias_ Howell 558
Genus _Tamias_ Illiger 559
Discussion 559
Conclusions 560
Literature Cited 561

ILLUSTRATIONS

Figs. 1-3. Dorsomedial Views of Malleus 549
Figs. 4-10. Lateral Views of Baculum 551
Figs. 11-12. Ventral Views of Hyoid Apparatus 552

INTRODUCTION

The supraspecific categories of the chipmunks, as in most other groups
of squirrels, have been a source of controversy for many years. Before
presenting new evidence and a review of older evidence bearing on the
problem, it seems desirable to review briefly in chronological order,
the taxonomic history of the genera and subgenera of the chipmunks.

HISTORICAL

Linnaeus (1758:64) described the eastern North American chipmunks under
the name _Sciurus striatus_ and based his description on that of Catesby
(1743:75). The Asiatic chipmunk was first described, under the name
_Sciurus sibiricus_, by Laxmann (1769:69). Schreber (1785, 4:790)
separated the Asiatic and North American chipmunks into the Asiatic and
American varieties. Gmelin (1788:50) followed Schreber and, employing
trinomials, used the names _Sciurus striatus asiaticus_ and _S. s.
americanus_. Illiger (1811:83) proposed _Tamias_ as the generic name of
the chipmunk of eastern North America. Say (1823:45) described _Sciurus
quadrivittatus_, the first species of chipmunk known from western North
America.

Trouessart (1880:86-87) proposed _Eutamias_ as the subgeneric name to
include the western North American and Asiatic chipmunks.

Merriam (1897:189-190) raised _Eutamias_ to full generic rank. In so
doing he neither listed nor described any characters but wrote that "it
will be o