REPTILES 217 



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

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



V. valericB B and 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. V. elegans Kennicott. Similar to V. valericB. but difTering in 

 having scales in 17 rows: Indiana and Illinois to Texas. 



31. Thamnophis Fitzinger. {Eutcsnia 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 



ai Lateral stripes anteriorly on third and fourth scale rows. 



bi lail long; snake shm; stripes narrow and bright T. sauritus. 



bo Tail shorter; snake stout; stripes broader and vaguer T. radix. 



S.2 Lateral stripes on third scale row T. marcianus. 



as Lateral stripes on second and third scale rows. 



bi Upper labials normally 8 T. ordinoides. 



b2 Upper labials normally 7. 



Ci Eye small; scales usually 17; posterior and anterior chin 



shields equal T. ordinoides. 



Co Eye large; scales 19; posterior chin shield much the larger . . T. sirtalis. 

 bs Upper labials 5 or 6 T. linealus. 



T. sirtalis (L.) Common garter snake (Fig. 1 23) . Length 750 mm. ; 

 tail 130 mm.; color very variable, varying from greenish to blackish, 

 with 3 yellowish, longitudinal stripes and 2 or 3 series of black spots on 

 each side, both stripes and spots being indistinct in some cases; belly 

 greenish: entire country; our commonest snake. 



Subspecies of T. sirtalis 



T. s. sirtalis (L.) Typical form: eastern and central States; west- 

 ward to Minnesota and INIissouri. 



T. s. concinnus (Hallowell). A series of reddish, vertically elongated 

 spots on each side; ground color black; throat and lips red; belly black: 

 coast region of Oregon, Washington and British Columbia. 



