734 13. COLUBRIDM 



Pituophis catenijcr anntctens Van Denburch & Slevin, Proc. Cal. Acad. 



Sci., Ser. 4, Vol. IX, 1919, p. ai6 (part). 

 Pituophis catenijer rutilus Van Denburgh, Proc. Cal. Acad. Sci., Ser. 



4, Vol. X, No. I, 1920, p. 24, pi. 2, fig. 2 (type locality, Tucson, 



Pima County, Arizona). 



Description. — Head somewhat flat-topped, with snout 

 projecting and rather narrower. Temporal regions not swol- 

 len. Rostral plate very large, prominent, not very narrow, 

 often recurved between internasals on top of snout; bounded 

 behind by internasal, anterior nasal, and first labial plates. 

 Plates on top of head are a pair of internasals, a variable 

 number of prefrontals (normally four), a frontal, supra- 

 ocular of each side, and a pair of parietals. Anterior and 

 posterior nasals usually distinct. Loreal usually elongate. 

 Preocular usually one, occasionally two. Postoculars usually 

 three, often four, sometimes five. Supralabials usually 

 eight, often nine, rarely 10. Infralabials usually 12, often 

 13, sometimes 11 or 14. Temporals of first row varying 

 from two to five, usually four. Genials in two pairs, anter- 

 ior larger. Scales on body in 29 to 35 rows, usually 33, 

 keeled except in a varying number of rows on each side. 

 Anal plate not divided. Gastrosteges varying in number 

 from 221 to 258, males having from 221 to 237, females 

 from 227 to 258. Urosteges in two series of from 50 to 

 66, males having from 57 to 66, females from 50 to 60. 



The ground color is pale yellow or grayish yellow, some- 

 times more or less obscured by the spreading of the blotches 

 or the presence of dark keels on the scales, especially later- 

 ally and anteriorly. Along the middle of the back, from the 

 head to a point over the anus, is a series of from 37 to 55 

 (average 46) reddish brown blotches. The brown of these 

 blotches becomes darker and redder posteriorly. These 

 blotches often are margined with black. On the upper sur- 

 face of the tail are from 10 to 14 (average 12.5) dark red- 



