792 REPORT OF NATIONAL MUSEUM, 1898. 



throat white. The young are olive, with rhomboidal dorsal blotches; 

 beneath greenish white. 



Frontal plate much longer than broad, pentagonal, anterior margin 

 convex, the lateral strongly concave, the plate rapidly diminishing to 

 half its length, thence the sides nearly parallel, terminated by a rather 

 obtuse angle; a little shorter than the parietals. Snperciliaries large, 

 rather broad. Rostral rather broad and high, wedged to a slight 

 extent between the prefrontals. Eye large, its center before the middle 

 of the commissure and over the fourth labial. The lower anteorbital 

 very small, wedged in between the ui)per anteorbital, the loreal,the third 

 labial, and the eye. Loreal trapezoidal, oblique, moderate. Labials 

 above seven; the first, third, and fifth smaller than the rest, the third 

 and fourth entering into the orbit; the fourth the only one in contact 

 with the lower postorbital ; sixth and seventh largest. Lower labials 

 eight, the fifth much the largest. Two rows of temi)oral sc;iles between 

 the labials and occipitals. Exterior row of dorsal scales very large, 

 diminishing gradually on the back. Scales very thin, the posterior 

 angle moderately truncate, so as to give an elongated hexagonal shape 

 to the ex[)Osed portion. Exposed surface of exterior row nearly as 

 high as long. 



Color above uniform lustrous pitch black, beneath slate color, some- 

 times tinged with greenish white. Lower jaw and chin and sometimes 

 edge of the upper labials white. Specimens from the West and South- 

 west exhibit a more or less bright olive green with the whole under 

 surface greenish white to bright yellow. In one or two specimens 

 there is but one anteorbital. 



The young of this species are variegated in color instead of being 

 uniform. The ground color is dark olive, with a succession of darker 

 rhomboidal dorsal blotches from head to tail. These are about nine 

 scales wide, and four or five long, separated by lighter intervals, which, 

 narrow along the back, widen of course ra))idly toward the abdomen. 

 The edge of ea(;h scale is obsoletely lighter than the center, the dark 

 centers in some scales being of such intensity as to produce the impres- 

 sion of distinct spots, especially on the sides. Along the vertebral 

 region the margins of the blotches are narrowly dai ker, and those of 

 the intervals lighter than on the sides. Beneath greenish white, each 

 scutellawith from two to four dark spots on the edges. Top of head 

 yellowish gray, posterior margins of both pairs of frontals dark chest- 

 nut, as are the contiguous edges of the superciliaries and vertical, and 

 posterior edges of the superciliaries and occipitals as well as a small 

 blotch on the outer edge of the superciliaries, and a broad patch in the 

 center of the occipitals running up into the vertical. Sides of head 

 white, especially labials and orbitals; tinged with bluish behind the 

 eyes, and spotted with dark brown. 



Specimens over 18 inches lose the blotching, and become more and 



