CHECKLIST OF THE SNAKES OF MEXICO 135 



5a. Ventrals 165 ; 7 supralabials ; no dark or light collar ; three dark lines. 



coronadol 

 Ventrals 152 or less 6 



6. A light nnclml collar (may be broken medially) ; seven supralabials; 



five dark lines on body deppei 



No light collar; six supralabials; three dai'k lines t 



7. Lateral stripe on adjacent halves of fourth and fifth rows ; no preocular ; 



ventrals 114 ; caudals 39 martindelcampoi 



Lateral stripe on adjacent halves of third and fourth rows ; a preocular 

 (sometimes very minute) ; ventrals 119 to 132; caudals 27 to 

 35 calamarina 



8. Dorsal surface of body dark and the dark color sharply differentiated 



from lighter ventral color at ends of ventrals 9 



Dorsal surface of body dark or light, but, if dark, color not sharply differ- 

 entiated from lighter ventral color at ends of ventrals 10 



9. Sides of body darker than middorsal area, the two areas rather sharply 



differentiated and separated by a dim, narrow, light line ; ventrals 140 



to 154 ; caudals 49 to 53 cuniculator 



Sides of body not darker than or distinctly differentiated from color 



of middorsum 9a 



9a. Ventrals 149, caudals 56 in a male ; mental separated from chin shields. 



morgani 

 Ventrals 137 to 143, caudals 31 to 44 in males; mental in contact with 

 chin shields phrenitica 



10. Head of about same color as back, or, if darker, its color not sharply dif- 



ferentiated from that of back; (nid no light nuchal collar canula 



Head black or dark brown, sharply differentiated from color of back, or, 

 a light nuchal collar present 11 



11. Black head cap V-shaped, its apex extending three to five scale lengths 



posterior to parietals on middorsal line; no nuchal collar; body 



light 12 



Black head cap with a straight or slightly convex posterior margin; a 

 nuchal collar at least faintly visible, not necessarily dark-edged 

 behind; body dark or light 13 



12. Ventrals in males 136 to 150, in females 150 to 161 nigriceps nigriceps 



Ventrals in males 130 to 138, in females 141 to 150 nigriceps fumiceps 



13. Nuchal collar indistinct, of about one scale length, not dark-edged 



posteriorly (sometimes a few black dots) 14 



Nuchal collar very distinct, usually of more than one scale length, dark 

 edged posteriorly 18 



14. Black of head extending below angle of mouth onto gular scales, and 



posteriorly two or more scale lengths 16 



Black of head not extending below angle of mouth onto gular scales, 

 and posteriorly two or less scale lengths 15 



15. A fine, distinct, black, middorsal line ; 3 temporals ; ventrals 129 in type ; 



usually (?) 1 postocular hobartsmithi 



No middorsal dark line; 2 elongate temporals; ventrals 123 to 158; 

 usually 2 postoculars atriceps 



16. A light area bordering lip behind eye and extending to middle of pri- 



mary temporal ; naris much nearer upper than lower border of nasal- 16a 

 No light area as described; naris equidistant from upper and lower 

 borders of nasal 17 



