146 BULLETIN 187, UNITED STATES NATIONAL MUSEUM 



5. Blotches more than twice as long as intei'spaces ; no evidence middorsally 



of secondary bands or blotches paucimaculatus 



Blotches less than twice as long as spaces between ; usually secondary 

 bands or blotches present middorsally on some part of body 12 



6. Anterior dorsal blotch covering 15 or more scale lengths on middorsal line, 



involving 7 or more ventrals ; blotches usually gray or black 7 



Anterior dorsal blotch covering 13 or fewer scale lengths middorsally, 

 involving fewer than 7 ventrals 8 



7. Blotches little narrower laterally than dorsally, much broader on belly 



than interspaces fasciolata 



Blotches much narrower laterally than dorsally, on belly equal to or 

 narrower than white interspaces latifascia 



8. Blotches very narrow, a third length of interspaces; anterior border of 



first dorsal blotch 9 or 10 scales behind parietals vilkinsonii 



Blotches broader, little if any narrower than spaces between ; anterior 

 border of first dorsal blotch farther forward, not more than six scales 

 behind parietals 9 



9. Fifth and sixth labials entering orbit; anterior loreal split, an upper 



and lower ; tail white, unmarked, below f orbesi 



Fourth and fifth labials entering orbit; anterior loreal single; tail 

 marked below or not 10 



10. Bands on body 16 collaris 



Bands on body 22 or more 11 



11. A roughly Y-shaped mark on parietals, the arms forking just behind 



frontal, the mark usually enclosed by dark color posteriorly ; belly with 

 some, subcaudal surface with numerous dark marks ; blotches on body 



23 to 32 upsilon 



No similar mark on head ; dark color of head sharply truncate near poste- 

 rior edge of parietals, with a narrow or broad, light indentation along 

 parietal suture tau 



12. Total of ventrals plus caudals 358 to 376 biscutatus semirutus 



Total of ventrals plus caudals 341 to 359 biscutatus biscutatus 



TRIMORPHODON BISCUTATUS BISCUTATUS (Dnmeril, Bibron, and Dnmeril) 



Dipsas hiscutata Dum^eil, Bibron, and Dum^kil, Erp^tologie g^n^rale, vol. 7, 



pt. 2, 1854, pp. 1153-1154. 

 Trimorphodon biscutatus biscutatus Smith, Proc. U. S. Nat. Mus., vol. 91, 1941, pp. 



159-160, map fig. 38. 

 Trimorphodon major Cope, Proc. Amer. Philos. Soc, vol. 11, 1869, p. 153 (type 



locality, Tehuantepee; type, U.S.N.M. Nos. 3042-9, three cotypes). 



Type.—Mws. Hist. Nat. Paris. 



Type locality. — Mexico. 



Range. — The Pacific slopes of western Chiapas, westward and north- 

 ward to Morelos (known from the states of Chiapas, Morelos, and 

 Oaxaca; records from Guanajuato seem very doubtful.) 



TRIMORPHODON BISCUTATUS SEMIRUTUS Smith 



Trimorphodon biscutatus semirutus Smith, Proc. U. S. Nat. Mus., vol. 93, 1943, 

 pp. 492^93. 



Type.—V.^.'^M. No. 110410. 

 Type locality. — Acapulco, Guerrero. 



