28 COLTJBEID^. 



** Scales in 21 or 23 rows. rp_ 5i_ 



Third and fourth labials entering the eye . . 24. conspicillatus, 

 Fourth and fifth labials entering the eye . . 25. longissimus, p. 52. 



/3. A subocular below the prseooular. 

 * Scales in 23 or 25 rows. 



Scales feebly keeled ; ventrals 226-244 ; [p. 54. 



subcaudals 97-122 26. cUmacoplwrus, 



Scales strongly keeled ; ventrals 209-220 ; 



subcaudals 80-96 27. phyUophis, p. 55. 



Scales strongly keeled ; ventrals 173 ; sub- 

 caudals 70 28. davidi, p. 56. 



** Scales in 27 rows ; ventrals 268-274 ; subcaudals 

 97-99 29. moellendorffii, p. 56. 



6. Subcaudals 122-149 ; scales smooth or faintly keeled, in 

 23 to 27 rows ; ventrals 236-263. 



Two labials entering the eye; green above. 30. oxycepJidlus, p. 56 

 Three labials entering the eye ; tail black. . 31. janseni, p. 57. 



2. Anal usually divided ; scales in 17 or 19 rows ; ventrals 



193-210. 



a. Scales in 19 rows. 



a. Three labials entering the eye. 



No loreal; subcaudals 120-121 32. frenatus, p. 58. 



A loreal; subcaudals 91-107 33. prasinus, p. 59. 



/3. Two labials entering the eye ; subcaudals 70-96. 



3. Anal entire ; scales keeled. ^4. quadrivirgatus,^.5Q. 



a. Scales in 19 rows, 21 on the neck. 



All caudal scales keeled 35. melanurus, p. 60. 



Outer caudal scales smooth 36. radiatus, p. 61. 



b. Scales in 21 rows, 23 on the neck. 37. erythrurus, p. 62. 



c. Scales in 23 or 25 rows, 25 or 27 on the neck. 

 Eostral a little broader than deep ; three 



labials entering the eye 38. enganensis, p. 63. 



Eostral much broader than deep ; two la- 

 bials entering the eye 39. suhradiaius, p. 64. 



II. The portion of the rostral shield visible from above measuring 

 at least half its distance from the rostral. 



A. Scales smooth. 



Eostral deeper than broad ; anal usually 



divided 41. sccdaris, p. 65. 



Eostral as deep as broad; anal entire .... 42. arizonce, p. 66. 



