SYNOPSES AND DESCRIPTIONS. 41 



Scales in 17 rows; 

 anal entire; 



back plumbeous to black, in adults ; 



two labials in the orbit constrictor. 



one labial in the orbit mentovarius. 



(Masticophis:) 



Anal bifid; 



clingy white, mixed with brown, varying to black on the anterior 



half of the body ftagelliformis. 



reddish-brown; anterior scales darker in the center, posterior 



with a light spot at the base testaceus. 



color in longitudinal bands ; 



three preoculars ; brown darkening anteriorly 



aurigulus, 

 one preocular; 



bands broken into transverse blotches anteriorly 



mexicanus. 

 a yellow band on vertebral rows; a black line at ends of 

 ventrals spinalis. 



Scales in 15 rows ; 



a broad band of dark color on the back; flanks with narrow lines of 

 light color, separated by dark. taeniatus. 



Coluber constrictor, pi. IV, Jig. 3. 



Linne, 1758, Sysl. Nat., ed. X, I, 216; 17G6, ed. XII, I, 385. 



Elongate, slender, slightly compressed; head distinct from the neck, 

 long, narrow, angled in front, concave on the sides, crown flat, curving 

 downward near the snout; tail about one fourth of the total, slender. 

 Eyes large, over the third and fourth labials, pupil round. Mouth-cleft 

 deep, curved. Crown-shields normal. Prefrontals bent downward on the 

 side of the head. Rostral broad, very convex. Nasal in two parts, nostril 

 between. A loreal. Preoculars two, sometimes but one, lower very small, 

 in a notch between the second and third labials. Postoculars two (2 — 3), 

 lower resting on the fourth labial. Temporals 24-2-J-2. Labials seven 

 (7 — 8), fourth, sixth, and seventh larger. Infralabials nine, fifth very 



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