304 PROCEEDINGS OF THE NATIONAL MUSEUM vol. lie 



in the Guadalupes, where most specimens approximate D. p. arnyi in 

 dorsal and ventral counts and D. p. regalis in frequency of temporal 

 combinations; however, a male from Walnut Canyon is closest to 

 D. p. regalis in having 206 ventrals. On the basis of clinal variation 

 and intermediate coloration, ringneck snakes from the Guadalupe 



G 



99 



F — caiti. 9 



II 



5 

 A 1 12 



13 



dcf 



> 



160 170 180 190 200 210 220 230 240 250 



VENTRAL SCALES 



Figure 10. — Variation in the number of ventral scales of Diadophis punctatus from the 

 Southwest and Mexico. (Solid circles = intergrades; hollow circle = a specimen from 

 Durango. See table 10 for other provenance data and figure 8 for explanation of diagram.) 



Mountains south through Trans-Pecos, Texas, are considered inter- 

 grades between D. p. arnyi and D. p. regalis. Perhaps this zone of 

 intergradation extends further north. Bragg and Dundee (1949) 

 reported D. p. arnyi seven miles south of Las Vegas, San Miguel 

 County, New Mexico; typical D. p. regalis occurs 65 miles to the west 

 in Sandoval County. 



West of the Guadalupe Mountains, ventral scale counts are uni- 

 formly high among specimens from central and western New Mexico, 

 Arizona, Utah, and northern Chihuahua (fig. 10). Zuni ringnecks 



