AMPHIBIA AND REPTILIA OF COLORADO 103 



Genus ZAMENIS Wagler 



Zamenis Wagler, Syst. Amph., p. 188, 1830. 



Bascanion Baird and Girard, Cat. N. Am. Reptiles, Pt. I, p. 93, 1853. 



Anal plate divided; scales smooth, in 15, 17 or sometimes 19 rows; 

 superior labials, 7 or 8; posterior maxillary teeth successively longer 

 than those in front; preoculars, 2, the lower much the smaller; long 

 and rather slender snakes. 



Snakes of this genus are popularly known as Black Snakes, Racers 

 and Coach whip Snakes. They are generally believed to constrict 

 their prey, which is not the case. For food they take particularly 

 small rodents, insects, and birds and eggs when they can get them. 

 All of the North American species are oviparous, laying from eight to 

 twenty-four eggs. Species of this genus are found in Central and 

 North America, Europe and Asia. 



Young specimens of the species of this genus are marked with 

 numerous cross bands of dark brown on a ground color of lighter brown. 

 As they grow older this pattern is either obscured or entirely obliter- 

 ated by the darker ground color of the adult. Specimens of all species 

 of this genus may be found in which these bands are fairly distinct 

 even in the adult. This is especially true of Z. laeniatus. 



Key to the Colorado Species of Zamenis 

 a. Scales in 15 rows (rarely 17); adult with 2 to 5 narrow stripes on each 

 side; belly yellowish and more or less spotted; upper labials, 8. 



Z. laeniatus (Hallowell). 

 aa. Scales in 17 rows (rarely 19); adult without lateral stripes; upper labials, 

 7 or 8. 



ft. Upper labials, 7 Z. constrictor (Linnaeus). 



bb. Upper labials, 8. . Z. flagellum (Shaw) . 



Zamenis constrictor (Linnaeus) 

 Black Snake; Blue Racer 

 Coluber constrictor Linnaeus, Syst. Nat., ed. X, p. 216, 1758. 

 Bascanium constrictor vetustum — Yarrow, Wheeler Survey, Vol. V, pp. 541- 

 542, 1875 (Pueblo, Colo.). 



Bascanium constrictor — Yarrow, U.S.N.M., Bull. 24, p. 108, 1882 (Pueblo, 

 Colo.). 



