104 UNIVERSITY OF COLORADO STUDIES 



Zamenis constrictor — Cope, Rept. U.S.N.M., pp. 796-797, 1898 (Pueblo and 

 Denver, Colo.). 



Dorsal scales smooth, in 17 or rarely 19 rows; superior labials, 7; 

 ventrals, 160 to 200; tail, one-fifth to one-third of the total length; 

 long, rather slender species, length up to six feet. 



Two subspecies of this snake, separated by their color and to some 

 extent by their range, are known. Both occur in Colorado. 



Z. constrictor constrictor (Linnaeus). — Dorsally, dark blue black to 

 shiny black ; under parts whitish to slate gray. Range, United States 

 east of the Rocky Mountains, and northern Mexico; quite rare in the 

 western part of its range, where it is almost completely replaced by 

 the following variety. 



Z. constrictor flaviventris (Say) . — Dorsally, bright, dark green to 

 olive green; ventral parts bright yellow to greenish yellow. Range, 

 United States west of the Mississippi River, south into Mexico. 



Colorado specimens. — Colorado State Historical and Natural History 

 Museum: Denver, June 5, 1902 (750 mm.), H. G. Smith; Lamar, June 20, 1904 

 (2 specimens, 325 and 1520 mm.), H. G. Smith; Yuma, June 12, 1906 (385 mm.), 

 H. G. Smith; Agricultural College Museum: Ft. Collins, 1906 (310 mm.), S. A. 

 Johnson; State Teachers' College Museum: Baca, Las Animas, and Weld counties, 

 A. E. Beardsley; reported by Cockerell from Boulder. 



Zamenis flagellum (Shaw) 

 Coachwhip Snake (Figures 32 and 33) 



Coluber flagellum Shaw, Gen. Zool., Vol. II, Pt. II, p. 475, 1802. 



Bascanium flagelliforme testaceum — Yarrow, Wheeler Survey, Vol. V, p. 542, 

 1875 (Pueblo, Colo.); Yarrow, U.S.N.M., Bull. 24, p. 112, 1882 (Pueblo, Colo.). 



Zamenis flagellum flagellum — Cope, Rept. U.S.N.M., p. 803, 1898 (Pueblo, 

 Colo.). 



Coluber teslaceus — Say, Long's Exped. Rocky Mis., p. 48, 1823 (probably near 

 the junction of Fountain Creek and the Arkansas River). 



Dorsal scales in 17, rarely 19, rows; superior labials, 8; ventrals, 

 170 to 220; tail one-fifth to one-third of the total length; slender 

 species, length up to eight feet. 



Anterior portion of the body dark brown to almost black, gradually 

 shading into light brown in the caudal region; ventral parts white, 



