26 Bl'LLETIX l.")4, UXITED STATES NATlOXAi^ MUSEUM 



20. Middorsal sti'ipc usually lighter and iiarrowi'i- than lateral stripes, wavy, 



complete or ineomi)lete; yellowish middorsal streak sometimes pre.sent 28. 



Middorsal stripe of .same intensity and width as lateral stripes, straight, 

 complete or incomplete; yellowish nuddorsal streak absent. 



C. sexlineatus perplexus (Baird and Girard). p. 122. 

 (Utah and Colorado, south through Arizona, New Mexico and western 

 Texas into northern Mexico.) 



27. Yellowish middorsal streak absent; area between two upper stripes essen- 



tially of same color as sides, often a trifle darker 28. 



Yellowish middorsal streak present; area l)etween two dorsal stripe.*-., at 



least in part, lighter than ground color of sides. 



C. sexlineatus gularis (Haird and (Jirard), p. 97. 

 (Oklahoma, Texas, Central Chihuahua and Sinaloa, south to Guatemala.) 



28. Ventral sui'faces predominantly light in color, unless stained (dark F<peci- 



mens usually appear to be black below, instead of blue or dark-b'.ack) ; 

 dorsal strl]i(>s often closer to each other than to the stripes below them. 



C. sexlineatus perplexus (Baird and Girard i, ]i. 122. 

 (Utah and Colorado, south through Arizona, New ^Mexico, and western 

 Texas into noi'thern Mexico.) 

 Ventral ?.urfaces usually suffused with dark bluish; dorsal stripes usual.y 

 closer to stripes below them than to each other. 



C. sexlineatus gularis (Baird and Girard), ]). 07. 

 (Oklahoma, Texas, central Chihuahua, and Sinaloa. south to Guate- 

 mala.) 



29. Posterior side of forearm covered with small or slightly enlarged 



granules 31. 



Posterior side of forearm with large scutes or polygenes 30. 



30. Ventral surfaces predominantly light in color, unless stained (normal 



specimens often with a little light blue, but darkened specimens appear 

 to be black below) ; yellowish middorsal s-treak absent. 



C. sexlineatus perplexus (Baird and Girard), p. 122. 

 (Utah and Colorado, south through Arizona, New ^Mexico, and western 

 Texas into northern Mexico.) 

 Ventral surfaces more or less suffused with dark bluish or blue-black; 

 yellowish middorsal streak or light area sometimes pres.ent. 



C. sexlineatus gularis (Baird and Girard), p. 97. 

 (Oklahoma, Texas, central Chihuahua, and Sinaloa, south to Guate- 

 mala.) 

 !>1. Dorsal and lateral markings besides spots present; back striped or reticu- 

 lated: sides often cross-barred 38. 



Back unicolor or more or less covered with small rounded spots; no 

 reticulations or cross-bars present on back or sides; dorsal markings 

 never with decided indications of longitudinal arrangement 32. 



32. Back and sides with small light spots, at least posteriorly 36. 



Back unicolor, unspotted, or with a few dorsal spots only 33. 



33. Under surfaces of tail and feet largely white, yellowish, black or slate— 34. 

 Under surfaces of tai'. and feet largely red or pinkish. 



C. tessellatus rubidus Cope, p. 199. 

 (Southern Uowcc ('alilnniia from Sau Mai'cos Island to La Paz Bay.) 



34. Supraoculars four; posterior supraocular granules usiuiUy large and few, 



often not extending forward past the posterior border of the third sup- 

 raocular, especially in the United States 3o. 



