Studies on the North American Representatives of Ephebomyrmex (Hymenoptera: Formicidae)

Pogonomyrmex (Ephebomyrmex) imberbiculus was described by W. M. Wheeler in 1902 and seven years later he added the descriptions of pima and townsendi. Since that time there has been surprisingly little additional inf.ormation published on these interesting ants. What has appeared has consisted largely .of locality records, but few of these have added much to our knowledge of the ranges of these insects. It is gratifying to be able to present a more complete picture of the distribution of our representatives of Ephebomyrmex, particularly since this clears up certain questions related to the taxonomic status of townsendi. It has also been possible to expand Wheeler’s account of the habits of imberbiculus, for it appears that these same habits are true of pima also. In past years the writer has been able to study 53 colonies of Ephebomyrmex at 40 stations. This study has shown that the ranges of both imberbiculus and pima are much more extensive than was formerly supposed. It has also shown that townsendi is a synonym of imberbiculus. Wheeler described townsendi in 1909 (1) on the basis of a single specimen from Chihuahua. It is hard to avoid the suspicion that one .of Wheeler’s reasons for giving townsendi specific status is the fact that the type specimen came from Mexico. .Certainly the structural features which distinguish townsendi from imberbiculus are not partictflarly impressive. They consist mainly of the sculptur.e of the postpetiole and the first gastric segment. Wheeler believed that in imberbiculus the postpetiole is