126 BULLETIN 187, UNITED STATES NATIONAL MUSEUM 



Genus SIBON Fitzinger *» 



Sibon Fitzinger, Neue Classification der Reptilien, 1S26, p. 31. 



Sibynon Fitzinger, Systema reptilium, 1843, p. 27 (type, Dlpsas nebulata 



Sclilegel ) . 

 Petalogiiafhns DuMiiRiL, Bibron, and Dum^eil, Erpetologie generale, vol. 7, 1854, 



p. 463 (type, Coluber nebulatus Linnaeus). 



Genotype. — Coluber nehulatus Linnaeus. 



Range. — Central Guerrero and central Veracruz southward on both 

 coasts to northern South America. 

 Species. — One. 



SIBON NEBULATUS (Linnaeus) 



Coluber sibon Linnaeus, Systema naturae, ed. 10, vol. 1, 1758, p. 222 (type local- 

 ity, Africa [in error?] ; location of type unknown)."' 



Sibon sibon Amaral, Mem. Inst. Butantan, vol. 4, 1929, p. 194. 



Coluber nebulatus Linnaeus, Systema naturae, ed. 10, vol. 1, 1758, p. 222." 



Petalognuthus nebuhitus Mocquard, Mission scientificiue au Mexique et dans 

 l'Am(5rique centrale, Kept., livr. 16, 1908, pp. 881-882, pi. 72, fig. 3. 



Sibon nebulatus Taylor, Univ. Kansas Sci. Bull., vol. 26, 1939 (1940), pp. 473^74. 



Type. — Roy. Mus. Stockholm. 



Type locality. — Africa (in error). 



Range. — Central Guerrero and central Veracruz southward on both 

 coasts, including Yucatan, to northern South America (recorded in 

 Mexico from the states of Campeche, Chiapas, Guerrero, Oaxaca, 

 Tabasco, Veracruz, and Yucatan). 



Genus SONORA Baird and Girard 



Sonora Baird and Girarb, Catalogue of North American reptiles, isn3. p. 117. — 

 Stickel, Proc. Biol. Soc. Washington, vol. 56, 1943, pp. 109-128 (review of 

 Mexican forms). 



Genotype. — Sonora seviiannulata Baird and Girard. 



Range. — Southern portion of the western half of the United States 

 north to Idaho, south through mainland Mexico to Guerrero and per- 

 haps Oaxaca, and through the northern two-thirds of Baja California. 



Species. — In all, 12 species and subspecies, certainly 10 and probably 

 11 occurring in Mexico. 



KEY TO MEXICAN FORMS OF SONORA *« 



1. Pattern either without cross bands or with one to many black cross 

 bands on a variously pigmented ground color, but pattern neither 

 based on nor including three diiTereut colors of cross bands ; nasal 

 usually entire, seldom sutured ; color pattern without sexual varia- 

 tion ; scale rows various {semiannulata group) 4 



'° See footnote for Dipsas, p. 49. 



°' If -siTjoH and ncbiilatitu are oonspeclfic. since page or position priority has no standing, 

 the name chosen hy the first reviser stands. As shown by Boulenger's synonymy (Cata- 

 logue of the snakes in tlie British Museum, vol. 2, 1894, p. 293), nehulatua has long been 

 used instead of sihon, granting their synonymy. 



