SYNOPSES AND DESCRIPTIONS. 61 



PiTYOPHIS. 



HolbrooL; 1842, N. A. Jlerp. IV, 7. 



Long, moderately stout, compressed; head distinct from the neck, sub- 

 conical, broad posteriorly, pointed at the muzzle; tail rather short. Eye 

 moderate, pupil round. Teeth equal, smooth. Crown-shields nine to 

 eleven. Prefrontals one to two pairs. Nasal divided. A loreal, rarely 

 suppressed. One to two prooculars. Postoculars two to five. Scales 

 keeled, in 27 to 35 rows. The individual variation is very great in 

 specimens belonging to species of this genus, particularly so in those of 

 the Rocky Mountains. 



PiTYOPHIS MELANOLEUCUS. 



CoiuBER MELANOLEtTCUS Davdin, 179!), Hid. Nat. Rept. VI, 409. 

 PiTvopiiis MELANOLEUCUS IIuTbrook, 1S42, N. A. Ilerp. IV, p. 7, pi. I. 



Long, moderately stout, slightly compressed; head moderate, distinct 

 from the neck, appearing sul)quadrangular when viewed from the front, 

 narrowing forward, conical or jiointed, crown slightly convex, A'ery broad 

 behind; snout prominent; tail short, rather less than one seventh of the 

 total, stout, tapering. Eye moderate, pupil round. Mouth-cleft deep, 

 slightly curving. Crown-shields more or less irregular, commonly two 

 pairs uf prefrontals. Rostral very prominent, narrow, swollen, extending 

 on the upj)er surface of the head, between the internasals. Internasals 

 short, wide. Outer prefrontals extending on the side of the face to the 

 loreal, inner narrow posteriorly. Frontal broad anteriorly. Supra ciliaries 

 prominent, broadening backward. Parietals large, nearly as wide as long. 

 Nasal in two parts, nostril between. Loreal small, sometimes united with 

 adjacent plates. One jjreocular. Postoculars three to four. Two or more 

 temporals in contact with the postoculars, sometimes broken into small 

 scales. Labials eight, fourth below the eye, fifth under the postoi'bital, 

 seventh largest. Lifralabials thirteen to fourteen, fifth and seventh large, 

 hinder very small. A i)air of large submentals, followed by a pair of 

 smaller ones, which are separated by a pair of small plates. Scales 

 lozenge-shaped, usually in 27 or 29 rows (ranging in the different varie- 

 ties from' 27 to 35), outer broad, lateral smooth, vertebral keeled. Ven- 

 trals 212 — 216, broad. Anal entire. Subcaudals 58 to 60 pairs. 



Color whitish, tinged with red on the back, witli a dorsal series of large 

 spots of dark brown or black — becoming bands posteriorly — thirty or mor^ 



