4-0. THAMNOPHIS 



behind by internasal, anterior nasal, and first labial plates. 

 Plates on top of head: a pair of internasals, a pair of pre- 

 frontals, a frontal, supraocular of each side, and a pair of 

 parietals. Anterior and posterior nasals distinct. One 

 loreal. One or rarely two preoculars and from two to four, 

 normally three, postoculars. Temporals normally one 

 followed by two, sometimes 1 + 1, 1+3, 2+2 or 2+3. 

 Seven, or rarely eight or nine, superior and eight to 11, 

 normally 10, inferior labials, fifth or sixth superior and 

 fifth, sixth, or seventh inferior usually largest, third and 

 fourth or fourth and fifth superior reaching eye, first pair 

 of inferior meeting on median line. Two pairs of genials, 

 posterior longer than anterior. Scales on body in 19, or 

 very rarely 21, rows, all keeled except sometimes the first 

 row of each side. Anal plate not divided. Gastrosteges 

 varying in number from 156 to 175j males having from 

 161 to 175, females 156 to 174. Urosteges in two series 

 of from 74 to 97; males having from 82 to 97, females 74 

 to 93; a few of the anterior rarely undivided. 



There are three light lines, one on the middle of the 

 back and one along the second and third rows of scales of 

 each side, but the lateral lines not infrequently blend with 

 the color of the belly. The dorsal line usually is bluish, 

 but may be yellow. The belly is bluish or yellowish, or 

 rarely slaty, and may have a black line or series of spots 

 near the tips of the gastrosteges. The head may be brown, 

 olive, or coppery red above, bluish or grayish laterally, 

 yellowish white below. The tail is colored like the back, 

 but less definitely. In some specimens the ground color 

 above is solid black, without a trace of red. In others there 

 are traces of red on the sides, chiefly on the skin between the 

 scales. In several the red is more extensive and forms small 

 irregular blotches on the sides. In a number these blotches 

 are larger, and extend up from the lateral line in definite 



