Jslatrix \irtlandii (Kennicott) Kirtland's Water Snake 

 (Regina \irtlandii Kennicott) 

 Back lengthwise striped or almost plain; belly yellow, with or without 

 dark stripes or spots; with nine or more lower labials 138. 



138. Belly yellow, with two rows of dark spots which sometimes fuse to form 



two stripes with irregular sides; back brown, with two dark stripes; 

 sides pale but unstriped; S. C. to La. 



J^atrix rigida (Say) Striped Water Snake 

 Belly yellow or with dark stripes; back with or without dark stripes; 

 with a pale stripe along each side (faint in adults) 139. 



139. Stripe along each side narrow, involving part of the first and second 



rows of scales; with two to four dark stripes on the belly; Wis. to Pa., 

 and southwards 



l^atrix septemvittata (Say) Queen or Moon Snake 

 Stripe along each side wider, involving the first three rows of scales; belly 

 plain yellow or with a central dark stripe; 111. to La. and Texas 

 T^atrix grahamn (B. 5? G.) Graham's Water Snake 



140. Usually v^'ith 21 to 25 rows of scales around the body (7S[. erythrogaster 



transversa sometimes with 27) ; usually with ten lower labials 141. 



Usually with 27 to 33 rows of scales (7\(. rhonihifera rhomhifera some' 



times with 25) ; usually with eleven or more lower labials 149. 



141. Belly almost plain yellowish or reddish, sometimes with dark shading on 



the front edges of the ventral plates 142. 



Belly usually with definite light or dark markings 143. 



142. Plain colored in the adult; Texas to Ohio and Wis. 



T^latrix erythrogaster erythrogaster (Forster) Red'bellied Water 

 Snake 

 With dark blotches on the back alternating for the entire length with 

 the dark blotches of the sides; Mo. to Okla. 



7\^atrzx erythrogaster transversa (Hallowell) Blotched Water 

 Snake 



143. With a row of light spots along the middle of the belly 144. 

 Belly with dark markings and without a central row of light spots 145. 



144. Back obscurely banded; Fla. 



J\latrix compressicauda (Kennicott) Salt-water Moccasin, 

 Flat-tailed Water Snake 

 Back with four dark stripes; Texas to Fla. 



l^latrix clar\n (B. ^ G.) Clark's Water Snake 



145. With 18 or less dark markings along the middle of the back; belly 



whitish, with squarish dark spots; Kansas to Texas and La. 



Jslatr^x sipedon confiuens (Blanchard) Yellow Water Snake 

 With 19 or more dark markings along the middle of the back 146. 



146. Usually with cross bands along the entire length of the back; with a dis- 



tinct light line from the eye to the angle of the jaw 147. 



With dark bands across the anterior part of the back and vv-ith alternat- 

 ing dorsal and lateral blotches posteriorly; light line from eye to angle 

 of jaw less distinct or absent 148. 



411 



