622 NORTH AMERICAN SNAKES COPE. 



The yoiin*,^ individuals of this genus frequently differ in coloration 

 from the adults, and the species may be arranged in two series accord- 

 ing to the coloration of the young, as follows: 



(1) Young transversely spotted or banded. B. constrictor] B. flag- 

 ell if or me. 



(2) Young longitudinally striped. B. semilineatum ; B. later ale ; B. 

 sckottii ; B. treniatum. 



Of the second series all retain the striped coloration to maturity, ex- 

 cepting the B. semilineatinn, where a trace only remains on the anterior 

 part of the body. The general characters of the species are as follows: 



I. Scales in seveuteeu rows; superior labials seven. (Froutal plate nearly as wide as 



superciliarios posteriorly ; muzzle ratiier produced ; colors not in stripes.) 

 Two labials bounding orbit below ; form robust ; colors generally uniform ; al ways 



so on lips and throat B. constrictor. 



One labial bounding orbit below ; form more slender ; more or less spotted on the 



lips and throat B. mcntovarium. 



II. Scales in nineteen rows; superior labials eight. (Frontal plate one-half as wide 



as superciliary behind; muzzle narrowed, produced.) 

 Slender; above, black; below, yellow />. piceum. 



III. Scales in seventeen rows; superior labials eight. (Frontal plate one-half width 



of superciliaries posteriorly ; form slender.) 

 Muzzle narrowed, more or less decurved ; without, or with dark shades or spots 



anteriorly ; young cross-spotted B,fta(jeUiforme. 



Muzzle narrowed; pale with a lateral brown stripe anteriorly : no temi>oral spot; 



young striped ....B. semilineatum. 



Muzzle flattened, wider; a continued yellow stripe on third and fourth rows of 



scales only ; dorsal scales brown ; a yellow temporal spot; belly yellow. 



B. laterale. 



IV. Scales in tilteen rows ; superior labials eight. (Form slender ; color in stripes.) 

 Muzzle elongate, narrow ; frontal plate more than half as wide as sai)erciliarie8 



l)Osteriorly ; two lateral yellow stripes on a dark ventral and dorsal ground ; 

 dorsal scales yellow-edged; no temporal spot B. schottii. 



Muzzle elongate, flattened ; frontal half aa wide as superciliary behind ; reddish 

 brown above and below, with two yellow stripes as in B. schottii. that on the 

 third and fourth rows black-edged and split by a black line ; colors above 

 alternately transversely darker and paler B, ornatum. 



Muzzle depressed, short ; frontal plate half as wide as superciliaries posteriorly ; 

 brown above to fourth rov.- of scales: beh)W and sides, yellow; latter with 

 four or Ave lines on middles of rows of scales B. ta'niatum. 



Some of the species above admitted are nearly allied, and young 

 8j)ecimens are sometimes not readily referred to their proper places. In 

 the hrst place, although the eyes of young vertebrata are relatively larger 

 than those of the adult, yet the superciliary plates in this genus en- 

 croach more on the frontal in mature than in young specimens, so that 

 in the former the frontal plate is more narrowed posteriorly than in the 

 latter. The color characters of young individuals of the B. laterale and 

 B. tmiiaium are sometimes not fully developed, so that their reference 

 is ditficult. In all of the species the head plates are pale-bordered in 

 the young, and this character may or may not continue to maturity in 

 the B. ta'niatum. The B. comtrictor and B. flayelliforme are cross-barred 



