48. CROTALUS 909 



f . Dorsal rhombs usually not enclosing light later- 

 al areas. 



C. atrox. p. 914. 



f. Dorsal rhombs usually enclosing light lateral 

 areas as pale as the ground color. Tortuga 

 Island. 



C. tortugensis. p. 918. 



e'. First supralabial usually divided transversely; 

 general coloration reddish, pinkish or yellowish, 

 ff . General coloration reddish, pinkish or yellow- 

 ish ; markings duller and less definite} dorsal 

 blotches not usually completely surrounded by 

 light margins ; gastrosteges usually more num- 

 erous. 



C. exsul. p. 919. 



ff 3 . General coloration yellowish; markings much 



brighter and more definite, less punctulate; 



dorsal blotches usually completely surrounded 



by light margins; gastrosteges usually fewer. 



C. lucasensis. p. 925. 



d*. Tail brownish or grayish with darker brown (rare- 

 ly in part blackish) cross-bands; light postocular 

 line, if present, reaching row of scales next above 

 supralabials at or posterior to corner of mouth, 

 if at all. 

 ee. Intervals between dorsal dark blotches less than 



length of blotches along midline. 

 f f f . Dorsal blotches large, forming a single series, 

 g. Rostral not wider than high, 

 h. Gastrosteges average more numerous (158 

 to 189); no vertical white line across mid- 

 dle of rostral plate nor two white lines on 

 side of head. 



