1901.] NATURAL SCIE>'CE3 OF PHILADELPHIA. 69 



Americau species of Diaclophis must be limited to three. Baird 

 and Girard established two others, which with a third of his own 

 making, Cope regards as subspecies of D. amabilis. In these 

 forms the chief differences are in the shape of the frontal and 

 supraocular plates, and in the extent to which the dark dorsal area 

 invades the two outer rows of scales. But a series of the eastern 

 form, D. pundatus, of all sizes, shows that exactly these differ- 

 ences, in that species, are age characters, and in a genus whose 

 included forms are so nearly similar, there can be little doubt that 

 they are so in amabilis as well. 



Key to the Species, 



17 rows of scales; 7 (8) upper labials; ventrals 237 or less, 



1. D. r eg alls. 

 15 rows of scales; 7 (8) upper labials; ventrals 210 or less, 



2. D. amabilis. 

 15 rows of scales; 8(7) upper labiols; ventrals 160 or less, 



3 D. 2)unctatus. 



Diadophis punctatus L. 



Coluber punctatus L., Syst. Nat., Ed. XII, 376 ; D. punctatus B. and 

 G., I. c, 112 ; D. punctatus and D. (nnabihs stictocjenys (part) Cope, 

 I. c, 616, 617, and Eep. Nat. Mus., 751, 750; Coronellu jnmctata 

 Boul., I. c, II, 206. 



Head not very distinct; head plates normal; in adults the fron- 

 tal is much narrowed behind and acute; oculars 2 (l)-2; tem- 

 porals 1-1; upper labials 8 (occ. 7); scales in 15 rows; ventrals 

 136-160; subcaudals 36-62. Leugth 355 mm. (tail ^b). 



In adults the color is bluish black or brownish above, covering 

 the whole of the dorsal scales and extending like a bar upon the 

 end of each ventral; the belly is yellow or orange, sometimes with 

 a series of transverse dark blotches in the middle of each ventral, 

 these are, however, often absent; there is usually a yellow half- 

 collar on the nape, half a scale to a full scale in width; the lower 

 half of the upper and the whole of the lower labials is yellow with 

 small spots of black. In the young, the back is bright reddish 

 brown or salmon color, which reaches only the upper border of the 

 second row of scales, and extends downward as the color deepens; 

 the top of the head is dark brown and the nuchal collar is bor- 

 dered behind by a band of the same dark color; the frontal plate 

 is also more angular in front and less tapering behind, than in the 

 adult. 



Hab. — North America, east of the Mississippi river. 



