1885.] '^•^^ [Cope. 



Three parietals ;■ 14-15 scales in a head length; color in longitudinal 



bands S. graciosus. 



%% Two or more rows of flat supraoculars. 



Three or two parietals ; 12-15 scales in a head length ; no bands 



S. grammicus. 

 Three parietals ; 18-23 scales in a head length ; color in narrow cross- 



lines 5. microlepidottis. 



Ill Scales larger ; ten and fewer in a head length. 



§ Two or more distinct parietals on each side. 

 Three parietals ; 9-10 scales in a head length; two or more bands; no 



collar -S. consohrinns. 



Two parietals ; no bands, a black collar from shoulder to shoulder across 



throat '?■• vwiparus. 



§§ One parietal ; sometimes a minute one on its posterior border. 



a. One row of large supraocular scales. 



b. Scales on side of neck and shoulder smaller. 



Two rows of spots on back »?. biseriatus. 



bb. Scales of side of neck, etc., larger. 

 Parietal scales not wider than interparietal, which is not wider than long ; 



9-10 scales in a head length ; femoral pores 12-17 8. undulatus. 



Like undulatus, but larger ; femoral pores 10 ; throat not blue ; brown 



spotted above 8. spinosus. 



Parietal scales wider than interparietal, which is not wider than long ; 



6-7 scales in a head length 8. zosteromus. 



Parietal scales as wide as interparietal, and all wider than long ; 7 scales 



in a head length S. melanorhinui. 



aa. Two rows of large supraocular scales. 

 One narrow parietal on each side ; a black vertical spot on each scapula ; 



green <?. tmnioenemis. 



ft A dark band or collar crossing the nape (sometimes interrupted). 

 1. Dorsal scales in parallel series. 



a. Dorsal scales in 25-35 series between occiput and groin. 



jS. One canthal scale ; dorsals strongly mucronate ; one row of large 

 supraoculars. 

 "Collar incomplete above ; head less than one-fifth of length of head and 



body ; throat blue ;' ' Bocourt 8. lunmi. 



Collar very narrow, not pale bordered ; a little interrupted above ; head 



less than one- fourth of head and body ; throat dark slate, yellow 



spotted 8. ferrariperezi. 



Collar complete, yellow bordered before and behind ; head about one-fifth 



head and body ; throat, belly and groin black 8. melanogaster. 



/5/9. Two canthal scales. 

 One large row of supraorbitals ; dorsal scales strongly mucronate ; collar 



distinctly interrupted at middle, yellow bordered ; throat and middle 



of belly yellowish-green serrifer. 



