Heterodon nasicus \ennerlyi (Kennicott) Southwestern Hog' 

 nosed Snake 

 With eight small scales around the a2;ygous; belly dark along mid-line; 

 111. to Mont, and southwards 



Heterodon nasicus nasicus (B. & G.) Western Hog-nosed Snake 



129. With 15 to 17 rows of scales around the anterior or middle of the body 



(not counting the ventral plates) 130. 



With 19 or more rows of scales around the body 135. 



130. With one internasal or with no preocular (prefrontals touching eyes) 



or both 131. 



With two internasals; with one or more preoculars; prefrontals not 



reaching eyes 132. 



131. Usually with six upper labials; with two internasals; smooth anteriorly, 



but with the scales near the tail keeled; brown above, usually with two 

 rows of small dark dots; belly yellowish; Ind. to Texas 



Haldea valeriae elegans (Kennicott) Western Ground Snake 

 (Virginia elegans Kennicott) 

 Usually with five upper labials; usually with one internasal; scales of 

 back keeled; brown above; yellow below; Va. to Fla. and Texas 

 Haldea stnatula (Linn.) Southern Ground Snake 

 (Potamophis striatulus (Linn.) ) 



132. Back and sides dark, with a faint lengthwise streak in the center of some 



of the scales, so that they appear to be keeled; belly red, with black 

 cross bars; some of the scales of the tail faintly keeled; N. C. to Fla. 

 Seminatrix pygaea (Cope) Mud or Black Swamp Snake 

 Scales of back keeled; color above brown or green; belly usually plain 

 colored 133. 



133. With a loreal plate; nostril situated in the middle of a single nasal plate; 



back green; belly yellowish; Conn, to N. M. 



Opheodrys aestivus (Linn.) Rough Green Snake 

 No loreal; nostril between two nasal plates; back brown; belly red or 

 pink 134. 



134. With 15 rows of scales around the body; belly red; with the dark color 



of the back extending on to the sides of the ventral plates; eastern and 

 central states 



Storeria occipitomaculata (Storer) Red-bellied Brown Snake 

 With 17 rows of scales; belly pinkish; eastern and central states 



Storeria de\ayi (Holbrook) De Kay's Little Brown Snake 



135. With less than 180 transverse plates on the belly before the anus; scales 



strongly keeled Water Snakes 136. 



With niore than 185 ventral plates; scales weakly keeled; abdomen flat' 

 tened, forming an angle with the sides 

 Rat Snakes, Chicken Snakes or Colubers 156. 



136. Normally with 19 rows of scales around the body 137. 

 Normally with 21 to 33 rows of scales 140. 



137. Back brown, with darker spots and blotches; belly red, with a row of 



dark spots on each side; with seven lower labials; Wis. to Kentucky 



410 



