SYNOPSES AND DESCRIPTIONS. 4k 
Seales 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 ; 
dingy white, mixed with brown, varying to black on the anterior 
half of the body Jlagelliformis. 
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 
auriqulus. 
one preocular ; 
bands broken into transverse blotches anteriorly 
MexICanNus. 
a yellow band on vertebral rows; a black line at ends of 
ventrals spinalis. 
Seales in 15 rows; 
a broad band of dark color on the back; flanks with narrow lines of 
light color, separated by dark. taeniatus. 
CotuBEr constrictor, pl. LV, fig. 3. 
Linné, 1758, Syst. Nat., ed. X, I, 216; 1766, 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—8), 
lower resting on the fourth labial. Temporals 2+2+2. Labials seven 
(7—8), fourth, sixth, and seventh larger. Infralabials nine, fifth very 
