We used 11 samples comprising 224 specimens collected between 1966 and 1999 in Chihuahua, México, and Texas to clarify aspects of color pattern and meristic variation in the notoriously difficult gonochoristic Cnemidophorus gularis-scalaris-septemvittatus complex which is characterized by enlarged mesoptychial scales and enlarged and platelike postantebrachial scales. We allocated populations represented in all SEPT-CMX samples except SEPT-CMX5 from northeastern Chihuahua to Cnemidophorus gularis septemvittatus Cope, 1892, type locality Marfa, Presidio County, Texas, represented by sample SEPT-TUS1. This allocation adds 28 newly discovered sites in Chihuahua to the single valid record previously known for the taxon in that state. Our study revealed that three taxonomically distinct forms, one in Trans-Pecos Texas east of Alamito Creek, Presidio County, and another in southern Coahuila, México (both beyond the scope of this study), were included in septemvittatus in a 1962 taxonomic revision. Clarification of the distribution and variation of C. g. septemvittatus in Chihuahua sets the stage for further systematic studies. Whiptail lizards in our SCAL-CMX samples from Chihuahua, for which only the name Cnemidophorus gularis scalaris Cope, 1892, is available, represent two forms distinguishable from each other and from C. g. septemvittatus on the basis of color patterns that remain distinct through ontogeny. Further sampling of Cnemidophorus populations in Chihuahua will be required to fully resolve the scalaris problem.