292 PROCEEDINGS OF THE ACADEMY OF [Marcll, 



Eutaenia sirtalis. 



Coluber sirtalis L., Syst. Nat., Ed. X, p. 222 (1758). 



The usual scutellation in this species is 19 rows and 7 upper labials, 

 a formula which is very constant in the east, but in western forms 17 

 to 21 rows, or 6 to 8 labials sometimes occur. The lateral stripe is on 

 the second and third rows. Compared with E. elegans it is larger 

 and stouter, with a moderately large head. The posterior chin- 

 shields are much longer than the anterior. East of the Mississippi 

 river red is rarely developed, but I have seen one E.s. sirtalis hom'!>lorth 

 Carolina which showed much of that color upon the sides, and another 

 from Pennsylvania, in my own collection, is marked slightly with it 

 on the flanks, but from the great plains westward there is a general 

 disposition in reptiles to develop red, and it is more or less present 

 in most subspecies of E. sirtalis from those parts. 



Eutaenia sirtalis parietalis- 



Coluber parietalis Say, Long's Exp. to Rocky Mts., I, p. 186 (1823). 

 Coluber infernalis Blainville, Nouv. Ann. Hist. Nat., IV, 1835, p. 291, PL 



XXVI, fig. 3. 

 Tropidonotus concinnus Hallow., Proc. Acad. Nat. Sci. Pliila., 1852, p. 182. 

 Eutoenia dorsalis B. and G., Cat. No. Am. Serp., p. 31 (1853). 

 Eutcenia ordinoides B. and G., Z. c, p. 33. 

 E. sirtalis tetratania Cope (Fide Yarrow) ; LT. S. Geol. Surv. W. of 100th 



Mer., V, p. ,546 (1875), and Proc. U. S. Nat. Mas., XIV, p. 664. 

 E. sirtalis trilineata (part) Cope, Proc. U. S. Nat. Mus., XIV, p. 665 (1892). 



E. s. parietalis has a range quite as wide as E. c. vagrans, for while 

 it is absent from Arizona, and appears to be rare in Utah, it extends 

 farther to the east on the plains. The scutellation is 19 rows and 

 7 labials, but now and then it has S labials, and more rarely 21 rows. 

 It is ordinarily dark brown, with the spots more or less obscured and 

 the lower row separated by red which shows on the skin and usuaUy on 

 the scales in life, though much of it quickly fades in spirits. The small 

 dark spots on the ends of the ventrals and the dark margins to the 

 labials are either present or absent. The belly is yellow, various 

 shades of slate, or almost black in dark specimens. The outer row of 

 scales is often smooth, but sometimes weakly keeled. 



There is much difference in the amount and distribution of the red, 

 especially in those from the Pacific coast, and there is a tendency 

 toward melanism, strongly marked in the moist region of Oregon and 

 Washington. In conformity with the law of color development in 

 snakes this excess of pigment shows first upon the dorsal surface 

 adjacent to the vertebral stripe, sometimes obscuring part or the 

 whole of the upper row of spots (E. dorsalis) ; when it extends down 

 far enough to reach the upper border of the lower row, these are left as 



