CHECKLIST OF THE SNAKES OF MEXICO 169 



THAMNOPHIS VICINUS Smith 



Thamnophis vicinus Smith, Zoologica, vol. 27, 1942, pp. 104-106. 



Type.—E. H. Taylor-H. M. Smith Coll. No. 21530. 

 Type locality. — Temaxcal, Michoacan. 



Range. — ^Known only from central Michoacan (the type locality and 

 Morelia). 



Family ELAPIDAE Boie 



Elapidae Boie, Isis, 1827, p. 510. 

 Type. — Elups Schneider. 



Genus MICRUROIDES Schmidt 



Micruroides Schmidt, Bull. Antiv. Inst Amer., vol. 2, No. 3, 1928, pp. 63-64. 



Genotype. — Elaps euryxam,thus Kennicott. 



Range. — Arizona and southern New Mexico, possibly extreme south- 

 western Utah; Sonora, Tiburon Island, and western Cliihuahua. 

 Species. — One. 



MICRUROIDES EUKYXANTHUS (Kennicott) 



Elaps eiiryxanthus Kennicott, Proc. Acad. Nat. Sci. Philadelphia, 1860, pp. 



837-33S. 

 Micruroides euryxanthus Schmidt, Bull. Antiv. Inst. Amer., vol. 2, No. 3, 1928, 



pp. 63-64. — DiTMAKS, Reptiles of North America, 1936, p. 313, pi. 90, lower 



fig. (in color). 



rype.— U.S.N.M. No. 1122. 

 Type locality. — Sonora. 



Range. — Arizona and southern New Mexico, possibly extreme south- 

 western Utah ; Sonora, Tiburon Island, and western Chihuahua. 



Genus MICRURUS Wagler 



Micrurus Wagler, in Spix, Serpeutium Brasiliensium . . ., 1824, p. 48. — Schmidt, 

 Publ. Field Mus. Nat. Hist., zool. ser., vol. 20, 1933, pp. 29-40; vol. 20, 

 1936, pp. 205-216, figs. 24-27 (Mexican and Central American species). 



Genotype. — Micrurus spixii Wagler. 



Range. — Southern United States to Uruguay, northern Argentina, 

 Bolivia, and Peru. 



Species. — Twenty species and subspecies occur in Mexico, and about. 

 45 are extralimital. 



KEY TO MEXICAN FORMS OF MICRURUS «" 



1. Black bands in triads, and outer band of triad about as wide as median 



ring; red rings present only between the triads, not within them 2 



Black bands single, not in triads 3 



^ starred forms in the key have keeled supraanal scales in adult males (not known in 

 laticollaris, and In brotoni they may be present or absent). 



