REPTILES 227 



S. occipitomaculata (Storer). Red-bellied snake. Length 250 mm.; 

 tail 60 mm.; color chestnut brown or grayish with a lighter middorsal 

 stripe bordered with dark dots; belly red; upper labials 5 or 6; scales 

 in 15 rows: eastern and central States; westward to Kansas; south- 

 ward into Mexico. 



29. Potamophis Fitzinger (Haldea Baird & Girard). Small snakes 

 with keeled scales in 17 rows; head distinct from the neck and very 

 narrow and pointed: i species. 



P. striatulus (L.) Length 280 mm.; tail 40 mm.; color grayish or 

 reddish brown; belly red; ventrals 119 to 130; upper labials 5: southern 

 and central States; northward into Virginia east of the mountains and 

 into Minnesota west of them; southwestward into Texas; common in 

 damp woods, under the bark of fallen trees and stones; viviparous. 



30. Amphiardis Cope. Small snakes with indistinct head; scales 

 keeled; anal plate divided; 2 internasals: i species. 



A. inornatus (Garman). Length 250 mm.; tail 45 mm.; color uni- 

 form brownish olive; ventrals whitish : Texas and Oklahoma. 



31. Virginia Baird & Girard. Small snakes with smooth scales in 

 15 to 17 rows; upper labials 6, ventrals 125: 2 species. 



V. valericE B. & G. Length 180 mm.; tail 30 mm.; color grayish 

 brown or chestnut, with minute black dots; belly yellowish white; 

 scales in 15 rows: southern and central States; northward into New 

 Jersey; westward to Tennessee; common; secretive. 



V. elegans Kennicott. Similar to F. valericB, but differing in 

 having scales in 1 7 rows : Indiana and Ilhnois to Texas. 



32. Thanmophis Fitzinger. {Eutmiia Baird & Girard). Garter 

 snakes. Rather small, slender snakes, with a distinct head and keeled 

 scales in 17 to 23 rows; upper labials usually 7 or 8; 3 longitudinal, more 

 or less yellowish stripes; also several series of spots usually present; 

 ventrals 130 to 180: about 24 species, all North American; 11 species in 

 the United States, all viviparous; terrestrial and often aquatic, feeding 

 on frogs, toads, worms and other cold blooded animals. 



Key to the United States Species of Thamnophis 



El Scales in 19 rows, 

 bi Upper labials 7. 



Ci Lateral stripes on second and third rows of scales T. sirtalis. 



Co Lateral stripes on second, third and fourth rows of scales. . . .T. hutleri. 



C3 Lateral stripes on third and fourth rows of scales T. sauritus. 



bo Upper labials 8. 



Ci In the central States T. proximus. 



