52 BULLETIN 18 7, UNITED STATES NATIONAL MUSEUM 



KEY TO MEXICAN FORMS OF DRYADOPHIS 



1. Dorsal scales largely outlined with black in adults ; subcaudals 116 to 140. 



melanolonius melanolomus 

 Dorsal scales not mostly outlined with black ; adults nearly uuicolor above ; 

 subcaudals 120 or less 2 



2. Ventrals usually 179 or less ; young cross-barred or with lateral light lines. 



melanolomus veraecrucis 

 Ventrals usually ISO or more ; young cross-barred 3 



3. Markings on chin, gular region and anterior part of belly very poorly 



defined, except in young; dorsal scales uniform light olive in adults, 

 practically without evidence of remnants of the dark juvenile markings^ 4 

 Chin and anterior part of belly checkered very prominently in young, 

 moderately so in adults; dorsal scales with fairly distinct black edging. 



m.elanolomus slevini 



4. Caudals 103 to 112 melanolomus tehuanae 



Caudals 113 to 118 melanolomus stuarti 



DRYADOPHIS MELANOLOMUS MELANOLOMUS (Cope) 



MasticophU melanolomus Cope, Proc. Acad. Nat. Sci. Philadelphia, vol. 20, 1868, 



p. 134. 

 Dryadophis melanolomus melanolomus Stuart, Misc. Publ. Mus. Zool. Univ. 



Michigan, No. 49, 1941, pp. 88-91, pi. 4, fig. 4 (body pattern), map 4. 



Type.—V. S. N. M. No. 24985. 

 Type locality. — Yucatan. 



Range. — Northern and eastern portions of the Yucatan Peninsula 

 (known in Mexico from several localities in Yucatan). 



DRYADOPHIS MELANOLOMUS SLEVINI (Stuart) 



Eudryas slevvni Stuabt, Occ. Pap. Mus. Zool. Univ. Michigan, No. 2-54, 1933, p. 9. 

 Dryadophis melanolomus slevini Stxtart, Misc. Publ. Mus. Zool. Univ. Michigan, 



No. 49, 1941, pp. 93-95, pi. 4, fig. 6 (body pattern), map 4.— Smith, Proc. U. S. 



Nat. Mus., vol. 93, 1943, p. 418. 



Type.—C^Vii. Acad. Sci. No. 58679. 



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

 Range. — Tres Marias Islands (Imown only from Maria Madre and 

 Maria Magdalena) . 



DRYADOPHIS MELANOLOMUS STUARTI Smith 



Dryadophis melanolomus stuarti Smith, Proc. U. S. Nat. Mus., vol. 93, 1943, pp. 

 418-420. 



Type.—\]. S. N. M. No. 110924. 



Type locality. — ^Acapulco, Guerrero. 



Range. — Pacific slopes from Colima southward to Chiapas, ex- 

 clusive of the Isthmus of Tehuantepec (recorded from the states of 

 Colima, Guerrero, and Chiapas). 



