(i. Frontal at least twice as broad as the supra- 

 ocular. 



t Frontal as long as the parietals 9. C. nuchalis p. 157. 



tl Frontal shorter than the parietals. 

 aa. Rostral more broad than deep. 



1. Ventrals 129 — 176; subcaudals I2 — 31. 

 X Diameter of the eye equals its 



distance from the mouth. 



O Frontal more than twice as broad 



as supraocular 10. C sumairana p. 157. 



00 Frontal twice as broad as supra- 

 ocular; six white vertical spots on 



each side of the body anteriorly. II. C. elegans p. 158. 

 XX Diameter of the eye one time and 

 one third its distance from the 

 mouth 12. C siinalurensis p. 159. 



2. Ventrals 211 — 235; subcaudals 10 — 13. 13. C. gracilis p. 159. 

 bb. Rostral as broad as deep. 



1. Frontal four times as broad as the 

 supraocular; ventrals 156 — 179; sub- 

 caudals 14 — 24 14- <^; acutii-ostris p. 160. 



2. Frontal twice as broad as the supra- 

 ocular. 



X Subcaudals white, 14; ventrals 154. 15. C. carta p. 160. 

 XX Subcaudals II — 2i, with two white 

 bands, enclosing a dark one; ventrals 



130 — 187 16. C. midlcri p. 161. 



2. First lower labial in contact with its fellow. 

 a. A praeocular; a postocular. 



X Frontal not more than twice as broad as 

 the supraocular. 

 t Diameter of the eye much more than its 



distance from the mouth 17. C. cvcrctti p. l6l. 



tt Diameter of the eye not more than its 

 distance from the mouth. 



aa. Anal divided 18. C. occipitalis p. 162. 



bb. Anal entire. 



O First and second labials subequal. 



1. Ventrals 151 — 200; subcaudals 



15 — 30 19. C. virgtilata p. 162. 



2. Ventrals 123 — 146; subcaudals 



24 — 27 20. C. lautensis p. 163. 



00 Second labial larger than first. 



