72 BULLETIN 18 7, UNITED STATES NATIONAL MUSEUM 



Occ. Pap. California Acad. Sci., vol. 10, 1922, pp. 6.55-658, pi. 62.— Ditmars, 

 Reptiles of North America, 1936, p. 295, pi. 84, figs. 6, 8, pi. 87. 

 Heterodon nasicus nasicus Cope, Proc. U. S. Nat. Mus., vol. 14, 1891, p. 645 ; Ann. 

 Rep. U. S. Nat. Mus., 1898 (1900), pp. 774-777, fig. 168.— Dunkle and Smith, 

 Occ. Pap. Mus. Zool. Univ. Michigan, No. 363, 1937, pp. 9-10. 



Type. — U. S. Nat. Mus., apparently lost. 



Type locality. — Texas. 



Range. — Southwestern Iowa, Kansas, and South Dakota west to 

 Montana and south to central Texas, central New Mexico, central 

 Arizona, and northern Sonora, excluding the extreme southeastern 

 corner of Arizona; eastward in northern Illinois and Indiana (the 

 only known Mexican specimen is from "Sonora," presumably central 

 northern Sonora, if correct). 



HETERODON NASICUS KENNERLYI Eennicott 



Heterodon kennerlyi Kennicott, Proc. Acad. Nat. Sci. Philadelphia, vol. 12, 1860, 



pp. 336-337. 

 [Heterodori nasicus] Kennerlyi Bocoxtrt, Mission scientifique au Mexique et dans 



I'Am^rlique Centrale, Kept, livr. 10, 1886, p. 606, pi. 38, fig. 2.— Cope, Ann. 



Rep. U. S. Nat. Mus., 1898 (1900), pp. 773-774.— Dunkle and Smith, Occ. 



Pap. Mus. Zool. Univ. Michigan, No. 363, 1937, pp. 9-10.— Smith, Proc. U. S. 



Nat. Mus., vol. 98, 1943, pp. 432-433. 



:rype.— U.S.N.M. No. 1282, two cotypes. 



Type locality. — Restricted to "Lower Rio Grande," Tex. (included 

 also "Sonora"). 



Range. — Southern Texas, southern New Mexico, and southeastern 

 Arizona, south to central Zacatecas and central San Luis Potosi 

 (known from the Mexican states of Chihuahua, Coahuila, Durango, 

 San Luis Potosi, Tamaulipas, and Zacatecas ; very doubtfully recorded 

 from "Sonora"). 



Genus HYPSIGLENA Cope 



Hypsiglena Cope, Proc. Acad. Nat, Sci. Philadelphia, vol. 12, 1860, p. 246. — Taylob, 



Univ. Kansas Sci. Bull., vol. 25, 1938 (1939), pp. 367-368. 

 Pseudodipsas Peters, Monatsb. Akad. Wiss. Berlin, 1860, p. 521 (type, P. fallax). 

 Comastes Jan, Elenco sistematico degli Ofidi, 1863, p. 102 (type, C. quincunciatus) . 



Genotype. — Hypsiglena ochrorhynchus Cope. 



Range. — Southern Idaho and northern California south and east 

 through Baja California and central Texas to central Mexico, thence 

 southward along the Pacific coast of Central America perhaps to 

 Ecuador and Venezuela. 



Species. — Six species and subspecies, all occurring in Mexico. 



KEY TO FORMS OF HYPSIGLENA 



1. A well-defined, light nuchal collar 4 



No light nuchal collar ; nuchal blotch fused with postocular strii)e or not— 2 



2. Subcaudals 68, and parietals in contact with postoculars, in the single 



known specimen slevini 



