624 NORTH AMERICAN SNAKES COPE. 



Corijpliodon constrictor Dnm. aud Bibr., Erp. Gen., vii, 1854, p. 183; Giiutlier, Cat. Col. 



Suakes Brit. Mus., 18.58, p. 108; Jan. Icou. Gen. OficL, ii, 22, iii, Fig. 2 ; iv, Fig. 2; 



III, 48, iii, Fig. 17. 

 Coluber flaviv$ntris Say, in Long's Exped. Rocky Mts., ii, 1823, j). 185. 

 Coryphodon constrictor var. ftaviyentris Jan. Icon. Gen. Otid., ii,22, iii, Fig. 1 ; in, 48 vi, 



Fi-. 2. 

 Bascaiiium fremontii Bd. and Gird., Cat. Serp. N. Amer., 1853, p. 95. 

 Bascaniiim foxii Bd. aud Gird., 1. c. 96. 

 Bascanium vetmtus Bd. and Gird., 1. c. 97; Girard, U. S. Expl. Exped., 1858, p. 127, 



PI. VII, Figs. 12-19; Cooper, Pac. R. R. Report, xii, PI. ii, 1860, p. 301. 

 Bascanium constrictor \&x.vetiistuni(jo\)Q, Check List Batr. Rept. N. Amer., 1875, p. 40; 



Yarrow, U. S. G. Surv-. W. of lOOtli Mer., V, 1875, p. 241. 

 Coryphodon constrictor var. vetusltis Jau, Icon. Geu. Ofid., ii, 22, iv, Fig. 1. 

 li.iscaniam anthicmn Cope, Proc. Acad. Pbila., 1862, p. 338. 



Trausitioiis between the eastern black aud the western green forms 

 of this species are frequently met with in the region connecting the two 

 habitats. Thus, in Michigan the species is generally of a bluish green 

 or greenish blue tint above, aud is known as the " blue racer." Similar 

 specimens are in the National Museum from New Orleans, On the 

 yellow-bellied form of the plains, Say proposed his Coluber' flaviv entr is, 

 which was regarded as a distinct species by Hallowell and by Baird 

 and Girard. I, however, do uot find it to be more than a geographical 

 color race. The same color characterizes specimens from the Pacific 

 district, which are also inferior in size to Eastern individuals, aud fre- 

 quently have the head a little shorter. In spite of this fact they incline to 

 develop an additional labial jjlate, the number beiug occasionally in this 

 region eight on one or both sides. Thus, of eleven black Eastern spec- 

 imens only two have 8 superior labials on both sides. Of twenty-two 

 yellow-bellied specimens, three have the labials, 7 on one side and 8 on 

 the other, and nine have 8 on both sides. Of the twelve specimens 

 thus exceptioual, seven are from the Pacifis region aud five from the 

 Great Basin of Nevada and Utah, of the central region. This is the 

 Bascanium vetiistiim of Baird and Girard. In the tyj)e specimens the 

 sixth labial reaches the lower postocular ; but this is exceptional and 

 rarely occurs in California or other individuals. 



A remarkable color variety of this species was described by me 

 under the name of Bascanium anthimim. In this form the general 

 color is as in the dark bluish tinted variety, but numerous scales on all 

 l)arts of the body are a bright yellow. The yellow scales are rarely 

 regularly arranged, but sometimes show a tendency to a distribution in 

 chevron-shaped cross-bands. A specimen of this kind was sent me by 

 my friend. Prof. Pendleton King, as from near Baton liouge, Louisiana. 

 The typical specimen, which is in the National Museum, is of uncer- 

 tain locality, but was alleged to have been brought from Siam, most 

 probably erroneously. 



A black Bascanium was described by Baird and Girard as having 

 been brought from California, under the name of B. fremontii. The 

 specimen is a typical B. constrictor, and was taken probably to the 

 eastern region. The B. foxii Baird aud Girard is the same. 



