CHECKLIST OF THE SNAKES OF MEXICO 25 



Range. — Both coasts of extreme northern Mexico (mainland) south- 

 ward to northwestern Peru and central Argentina. 



Species. — Two species, one with six subspecies, are recognizable. 

 Two forms occur in Mexico. 



KEY TO MEXICAN FORMS OF CONSTRICTOR 



1. Ventrals 225-253 constrictor imperator 



Ventrals 258-259 constrictor sigma 



CONSTKICTOR CONSTRICTOR IMPERATOR (Daudin) 



Boa imperator Daudin, Histoire naturelle . . . reptiles, vol. 5, 1803, pp. 150- 

 152.— DITMAB8, Reptiles of tlie world, 1926, pi. 47 (lower fig.). 



Constrictor constrictor imperator Ihebing, Rev. Mus. Paulista, vol. 8, 1910, 

 p. 321.— Smith, Proc. U. S. Nat. Mus., vol. 93, 1943, pp. 409-411, 



Boa diviniloquax mexicana Jan, Elenco sistematico degli Ofidi, 1863, p. 23 (type 

 locality, Mexico; type in Tiibingen Mus.). 



Type. — Mus. Hist. Nat. Paris. 



Type locality. — Mexico. 



Range. — Central Tamaulipas and northern Sonora southward on 

 both coasts, including Yucatan, to South America; Maria Madre 

 Island, Tres Marias Islands (known from the states of Campeche, 

 Chiapas, Colima, Durango, Guerrero, Michoacan, Nayarit, Oaxaca, 

 Puebla, San Luis Potosi, Sinaloa, Sonora, Tamaulipas, Veracruz, 

 Yucatan). 



CONSTRICTOR CONSTRICTOR SIGMA Smith 



Constrictor constrictor sigma Smith, Proc. U. S. Nat. Mus., vol. 93, 1943, pp. 

 411-412. 



Type.— v. S. N. M. No. 24672. 



Type locality. — ^Maria Madre Island, Tres Marias Islands. 



Range. — Kjiown only from the type locality. 



Genus LICHANURA Cope 



Lichanura Cope, Proc. Acad. Nat. Sci. Philadelphia, vol. 13, 1861, p. 304. — Kiattbeb, 

 Trans. San Diego Soc. Nat. Hist., vol. 6, 1931, pp. 305-318, pi. 21, map (generic 

 revision). 



Genotype. — Lichanura trivirgata Cope. 



Range. — Baja California, southern California, southwestern Ari- 

 zona, and western Sonora. 



Species. — Three forms, all occurring in Mexico. 



KEY TO MEXICAN FORMS OF LICHANURA" 



1. Longitudinal stripes, if present, with edges uneven, zigzag, and ill- 

 defined roseofusca roseofusca 



Longitudinal stripes present and with even (but serrated) edges 2 



1* From Klauber, op. cit., p. 316. 



