CROCODILIANS, LIZARDS, AND SNAKES. 799 



differ equally from all others, the nearest approach to the Z. stejnegeri- 

 emus being made by abnormal individuals of the flavirentriH form of 

 Z. constrictor, which have eight superior labial shields. The very differ- 

 ent form of the loreal plate, and its subdivision, in the latter, together 

 with the contrast between the color of the head and the dorsum, will 

 distinguish it. 



ZAMENIS FLAGELLUM Shaw. 



Zamenis flageUiformifi Boulengeu, Cat. Snakes Brit. Mus., I, 1893, p. 389. 



Eight superior labials; scales in seventeen rows. Frontal plate nar- 

 rowed posteriorly, only half as wide as the supraoculars at the same 

 point. Muzzle projecting slightly conic, profile decurved ; form slender. 

 The young with transverse spots, more numerous than in Z. constrictor. 



This widely distributed species is represented by several color forms. 

 These may be aggregated into two types or subspecies, which differ as 

 follows: 



Colors pale, except in some regions, the head and adjacent parts dark colored. 



Z. flagelluni jlagellum Sbaw. 

 Black, except tlie belly, which is pink or yellowish Z. flagellum piceus Cope. 



The typical form occupies the Austroriparian and Sonoran districts, 

 while the Z. f. piceum is an inhabitant of the Sonoran only. 



ZAMENIS FLAGELLUM FLAGELLUM Shaw. 



BaHcanium flageUiforme Jlafjelliforme Cope, Check-list N. Anier. Batr. Kept., 



1875, p. 40. 

 Ang ids flag elliformis Catesby, Nat. Hist. Carolina, II, 1743, p. 54, pi. iv. 

 Coluber flagelluni Shaw, Gen. Zool., Ill, 1802, p. 475. 



Coluber flageUiformis Holbrook, N. Amer. Herpt., I, 1836, p. 107, pi. xix. 

 Bascanium flagelliforme bicinctum Yarrow, Proc. U. S. Nat. Mns., VI, 1883, p. 153. 

 Herpctodryas psanimophiH Sciilegel, Ess. Physion. Serpens., II, 1837, p. 

 Psammophis flageUiformis Holbkook, N. Amer. Herpt., 2d ed., Ill, 1842, p. 11, pi. 2. 

 Masiicophis flageUiformis Baird and Girard, Cat. N. Amer. Rept. Serp., 1853, p. 98. 

 Herpeiodrijas flageUiformis Dumeril and Bibron, Erp. G^u., VII, 1854, p. 210. — 



GuNTHER, Cat. Col. Snakes Brit. Mas., 1858, p. 118. 

 Coluber iestaceus Say, Long's Exped. Rocky Mountains, 1823, p. 48. — Holbrook, 



N. Amer. Herpt., Ill, 1842, p. 63.— Harlan, Jouru. Acad. Nat. Sci. Phila., V, 



1827, p. 348. 

 MaaticopMs iestaceus Baird, U. S. Mexican Bound. Surv., II, Pt. 2, Reptiles, p. 20, 



pi. XVI, 



Bascanium flagelliforme testaceum Cope, Check-list N. Amer. Batr. Kept., 1875, p. 40. 



Psammophis flarigularis Hallowell, Proc. Acad. Nat. Sci. Phila., 1852, p. 178. 



Masiicophis flarigularis Baird and Girard, Cat. N. Amer. Rept. Serp., 1853, p. 99. 



Herpetodryas flarigularis GiNTiiER, Cat. Col. Snakes Brit. Mus., 1858, p. 118. — 

 Hallowell, Rept. U. S. Pac. R. R. Surv., X, 1859, Williamson's Rept., p. 12. 

 Frontal plate wide in front, rapidly tapering, until at the anterior 

 third it is less than half as wide as in front, thence the sides are par- 

 allel, acutely pointed behind. Superciliaries very broad, projecting. 

 Parietals as long as the vertical. Prefrontals large, anterior smaller. 

 Eye large, its center considerably in advance of the middle of the com- 

 missure, and over the junction of the fourth and fifth labials. Upper 



