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 observed that the name _Eutamias_, proposed by Trouessart in 1880 as a subgenus of _Tamias_ is here adopted as a full genus. This is because of the conviction that the superficial resemblance between the two groups is accidental parallelism, in no way indicative of affinity. In fact the two groups, if my notion of their relationship is correct, had different ancestors, _Tamias_ being an offshoot of the ground-squirrels of the subgenus _Ictidomys_ of Allen, and _Eutamias_ of the subgenus _Ammospermophilus_, Merriam." Howell (1929:23) proposed _Neotamias_ as the subgeneric name for the chipmunks of western North America, of the genus _Eutamias_.