730 13. COLUBRIDA 
len. Rostral plate very large, prominent, not very narrow, 
often recurved between internasals on top of snout; bounded 
behind by internasal, anterior nasal, and first labial plates. 
Plates on top of head are a pair of internasals, a variable 
number of prefrontals (normally four), a frontal, supra- 
ocular of each side, and a pair of parietals. Anterior and 
posterior nasals usually distinct. Loreal usually elongate. 
Preoculars usually one, occasionally two. Postoculars usually 
three, often two. Supralabials usually eight, often nine. 
Infralabials usually 13, often 12, sometimes 11 or 14. 
Temporals of first row varying from two to five, usually 
four. Genials in two pairs, anterior larger. Scales on body 
in 27 to 33 rows, usually 29, keeled except in a varying 
number of rows on each side. Anal plate not divided. Gas- 
trosteges varying in number from 223 to 241, males having 
from 227 to 241, females from 223 to 240. Urosteges in 
two series of from 55 to 71, males having from 58 to 71, 
females from 55 to 62. 
The ground color is pale brownish or grayish yellow, 
sometimes more or less obscured by the spreading of the 
blotches or the presence of black or dark brown marks along 
the keels of its scales. Along the middle of the back, from 
the head to a point over the anus, is a series of from 50 to 
68 (average 58) dark blotches. These blotches are brown on 
the central part of the body but are black anteriorly and 
posteriorly. On the upper surface of the tail are from 14 
to 20 (average 16.5) blackish blotches. On the anterior 
portion of the body the blotches are more or less rounded, 
but posteriorly they tend to become quadrate. There are 
several series of alternating, often more or less confluent, 
dark blotches or spots on the sides. Across the top of the 
head, between the preocular plates, is a moderately narrow 
brown band, very definite and well-defined. There are 
similar bands or spots below the center of the eye and run- 
