The systematic status of the geographic variants of _Hypsiglena_ in México and southwestern United States has been commented on by several authors. Tanner (1944) considered _H. torquata_ and _H. ochrorhyncha_ to be distinct species; Bogert and Oliver (1945:379) and Duellman (1957b:238) presented evidence indicating that _H. torquata_ and _H. ochrorhyncha_ intergrade in Sinaloa and southern Sonora. In _Hypsiglena_ the scutellation, including the numbers of labials, dorsals, ventrals, and caudals, seem to vary in a clinal manner. Nevertheless, these snakes can be divided into two distinct populations on the basis of the nuchal color pattern, consisting of an _ochrorhyncha_-type (a broad dark nape-band, the lateral edges of which extend anteriorly and fuse with a postorbital stripe, and a narrow nape stripe extending from the posteromedian edges of the parietals to the dark nape band) and a _torquata_-type (a somewhat narrower dark nape-band bordered anteriorly by a pale nuchal area, and no dark nape stripe). Snakes having the _ochrorhyncha_-type of nuchal pattern are found on the Mexican Plateau from Michoacán northward into the desert regions of Sonora and the southwestern United States. Snakes having the _torquata_-type of pattern are found on the coastal lowlands and adjacent slopes of the Sierra Madre Occidental from southern Sinaloa to Colima and thence inland in the Balsas-Tepalcatepec Basin to Morelos and Guerrero. An exception is _Hypsiglena torquata dunklei_ from Forlón and San Fernando, Tamaulipas; it has the _torquata_-type of nuchal pattern. The distributional picture is somewhat complicated because some individuals having the _torquata_-type of nuchal pattern also have a faint nape stripe. If these are taken as exceptions, the general picture of distribution in México is _H. t. torquata_ on the Pacific lowlands from Sinaloa southward to the Balsas Basin and _H. t. ochrorhyncha_ on the Mexican Plateau. Smith (1943:433) resurrected _Hypsiglena jani_ Dugès for the snakes of the _ochrorhyncha_-type on the southern part of the Mexican Plateau. He stated that the southern specimens differed from northern ones in having a nuchal spot 9 or 10 scales in length, as compared with a spot 2 to 6 scales in length in northern specimens. A cursory examination of specimens from the areas between Arizona and Michoacán showed that there is a gradual increase in the size of the spot from north to south. If no other characters can be found to distinguish the populations, they should be considered as a single subspecies. _Hypsiglena affinis_ differs from _H. torquata_ in possessing 19 instead of 21 rows of dorsal scales. Additional material is needed from the western slopes of Jalisco and the Barrancas in Zacatecas and Durango, before definite allocation of _affinis_ can be made.