202 VERTEBRATE ANIMALS OF THE UNITED STATES 



62 Scales 19. 



fi Two internasals. 



gi Loreal present; parietal not in contact with 



labials Cemophora. 



g2 Loreal absent; parietal in contact with labials Stilosoma. 



io One internasal Liodytes. 



bs Anal double. 



Ci Scales 19 or more, 

 di Two internasals. 

 ei Preocular present. 



fi Pupil round; one preocular *..... Coniophanes. 



{2 Pupil vertically elliptic; 2-3 preoculars. 

 gi One loreal. 



hi Several rows of spots Hypsiglena. 



ha Crossbars Leptodeira. 



go Two loreals Trimorphodon. 



e-2 Xo preocular Ahastor. 



d; One internasal. 



ei Preocular present Liodytes. 



e2 Xo preocular Farancia. 



C: Scales 17 or less, 

 di Loreal present. 

 ei 2-3 preoculars. 



fi Rostral enlarged, patch-like Salvadora. 



{2 Rostral normal. 



gi 2-3 anterior temporals; lower preocular very • 



small, wedged between labials Coluber. 



g2 One anterior temporal; lower preocular like upper. 



hi Uniform grass green Liopeltis. 



h2 Black with a yellow neck ring Diadophis. 



Co One preocular. 

 fi Scales 17. 



gi Upper labials 7 Rhadincea. 



g2 Upper labials 8 Seminatrix. 



fo Scales less than 17. 



gi Grass green Liopeltis. 



g2 Not grass green. 



hi Belly with black cross lines Contia. 



ho Belly immaculate or with bands that 



encircle body Sonora. 



Cs Xo preocular. 



f 1 Scales 15-17 Virginia. 



i-x Scales 13 Chilomeniscus, 



d.2 No loreal. 



61 13 scale rows; southwestern states Chilomeniscus. 



eastern states Carphophis 



e2 15 scale rows Tantilla. 



63 17 scale rows. 



