40. THAMNOPHIS 835 
Description —Head distinct from neck, flat-topped, 
with narrow, rounded snout, and temporal regions some- 
times slightly swollen. Eye of moderate size. Rostral 
large, bounded behind by internasal, anterior nasal, and 
first labial plates. Plates on top of head: A pair of inter- 
nasals, a pair of prefrontals, a frontal, supraocular of each 
side, and a pair of parietals. Anterior and posterior nasals 
distinct. One loreal. Preoculars usually two, sometimes 
one, very rarely three. Postoculars normally three, some- 
times four, very rarely two or one. Temporals normally 
one, followed by two, sometimes 1+ 3. Superior labials 
normally eight, rarely seven. Inferior labials normally 
ten, rarely nine, 11 or eight. Usually the fifth, sixth or 
seventh superior and inferior labials largest, the fourth and 
fifth or third and fourth superior reaching eye, first pair 
of inferior meeting on median line. Two pairs of genials, 
posterior about equal in length to anterior. Scales on body 
in 21 or very rarely, 19 or 23 rows, all keeled except some- 
times the first row of each side. Anal plate not divided. 
Gastrosteges varying in number from 151 to 183, males 
having from 157 to 183, females from 151 to 176. Uros- 
teges in two series of from 63 to 97, males having from 76 
to 97, females from 63 to 91. 
The coloration usually is not different from that of 
typical Thamnophis ordinoides vagrans, except that the 
dorso-lateral regions usually are much darker. Because 
of this, the spots are less evident, but they may usually be 
made out. The upper lateral spots invade the edges of the 
dorsal line as in T. 0. vagrans. As in that subspecies also 
the gastrosteges are often marked basally and centrally 
with black or slate. The dorsal and lateral lines usually 
are quite distinct. Some specimens, however, are so dark 
as to conceal the dorsal spots, and one is black everywhere 
excepting the chin, throat, and a few bits of skin between 
