100 COLITBEIDiE. 



2, Prseocular separated from the frontal. 

 a. Ventrals 172-206 ; subcaudals 51-85. 



a. Eye rather small, not half the length of the snout. 



Black cross-bars disposed in threes ; head (^ 



black above 5. melanogenys, p. 105, 



Black cross-bars or annuU not disposed ^ 



in threes ; head black above 6. ddliatus, p. 106. 



Complete black annuli round the body ; ^- 



head uniform yellow or orange 7. formosus, p. 106. 



(3. Eye moderate, about half the length of the snout. 

 Loreal present, at least twice as long as 



deep 8. labialis, p. 107. 



Loreal often absent ; if present, short . . 9. dathratus, p. 107. 



h. Ventrals 232-236 j subcaudals 77-81. 



10. filzingeri, p. 108. ** 



B. Normally seven upper labials ; prseocular not or but jusfc- 

 reaching the upper surface of the head. 



1. 'Portion of rostral visible from above measuring one fourth 



to one third its distance from the frontal. 



Frontal a little longer than broad ; sub- 

 caudals 64^93 11. clcelia, p. 108. 



Frontal as long as broad; subcaudals 51. 12. maculatus, p. 110. 



2. Portion of rostral visible from above measuring about half 



its distance from the frontal. 



Praeocular moderate, just reaching the 



upper surface of the head ; subcaudals 



67-85 13. occvpitoluteus, p. 110, ' 



Prseocular very smaU. ; subcaudals 44-61, 14, rwiicw, p. Ill, 



II. Subcaudals single. 



A. Scales in 17 rows ; rostral broader than deep, forming an 



obtuse single posteriorly, its upper portion not more than 

 half as long as its distance from the frontal ; seven upper 

 labials 15. coronatus, p. 111. ' 



B. Scales in 19 rows ; normally eight upper labials. 



Eostral much broader than deep, forming 



an obtuse angle posteriorly, its upper 



portion not more than half as long as 



its distance from the frontal 16. neuwiedii, p. 112. 



Eostral nearly as deep as broad, forming 



a right or acute angle posteriorly, its 



upper portion at least two thirds its 



distance from the frontal 17. guerini, p. 113, 



