18 BULLETIN 114, UNITED STATES NATIONAL MUSEUM. 



Fuller knowledge of some forms that are now known from but few 

 specimens may be expected to reveal limits of variation that will 

 render invalid some of the distinctions nov/ used, but this contin- 

 gency has been guarded against as much as possible. 



KEY TO THE FORMS OF LAMPROPELTIS. 



a^. Pattern of narrow cross bands of black, the alternate bands mixed or split with 



red; ground color above, slate gray; head very distinct from neck, alterna, p. 247. 



(Davis Mountains, Texas.) 



a 2. Pattern not of narrow dorsal cross bands of black with the alternate bands mixed 



or split with red ; head usually only slightly distinct from neck. 



b^. Color pattern without red ^ and without dorsal blotches of brown or gray with 



black borders getulus group. 



c^ Scales chiefly black with sharply defined white or yellow spots (not light at 

 base shading gradually into a dark distal border) ; these yellow spots often 

 so grouped as to form 50 or more narrow cross bands on body and tail. 

 d^. Scale rows on middle of body 23 or 25; no light centers, dorsally, on the 



scales between the cross bands; head mostly black splendida, p. 26. 



(Southeastern Arizona to the ninety -seventh meridian; southern Texas, 

 and northern Mexico.) 

 d^. Scale rows on middle of body usually 21. 



e ^ A yellow spot on practically all of the dorsal scales holbrooki, p. 33. 



(Eastern Texas to southeastern Wyoming, east to eastern Illinois, and 

 south to the Gulf of Mexico.) 

 c 2. Scales between the dorsal cross bands without light centers or with only 



a very few small ones nigcr, p. 43. 



(Eastern Illinois to Ohio, south to central Alabama.) 

 c 2. Pattern in rings, cross bands, or stripes, or chiefly of scales white at base 

 shading gradually into a black distal border, but not chiefly of sharply 

 defined white or yellow spots on black scales. 



/^ Posterior chin shields nearly as long and nearly as wide as anterior, 

 in contact or separated by not more than one small scale; pattern 

 neither of rings nor of longitudinal stripes. 

 g ^ Many dorsal cross bands of white or yellow. 



h ^ Cross bands less than 50; 21 (sometimes 23) rows of scales. 



getulus, p. 49. 

 (From New Jersey to Mobile Bay and Central Florida.) 

 h 2. Cross bands more than 50, or nearly indistinguishable ; 23 (some- 

 times 21) rows of scales; scales between the cross bands usually 



white at base fioridana, p. 62. 



(Central to southern Florida.) 

 g"^. No dorsal cross bands distinguishable; dorsal scales light at base, 



shading gradually into a dark distal border brooJcsi, p. 66. 



(Extreme southern Florida.) 

 /2. Posterior chin shields generally much shorter and narrower than an- 

 terior and separated by one or two small scales; pattern of rings, or 

 of longitudinal stripes of white or yellowish. 

 i^. A dorsal longitudinal stripe, complete or interrupted. 

 j ^ Dorsal stripe white or j'^ellow, sharply defined on a dark brown 



or black ground color ccdijomiae, p. 94. 



(Fresno County, California to northern Lower California.) 



1 The red fades to whitish in alcohol, but it is sufficient, for the purpose of the key, to determine that 

 the pattern is in two colors instead of in three. 



