164 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 9i 



Hemipenis 23 caudals long; three large flounces, covering eight 

 caudal lengths; area of spines covering four caudal lengths. 



Color. — Dorsal color very light brownish gray, lighter in vertebral 

 region; 21 rhombs on body, 11 on tail; rhombs light brown, with a 

 slightly reddish tinge; a narrow black border on each rhomb, the 

 borders not extending below about the third scale row; rhombs ex- 

 tending to ventral scales; first five rhombs covering 13, 8, 9, 10, 10 

 scale lengths, last five 6, 5, 6, 6, 7 scale lengths, respectively (on mid- 

 dorsum) ; spaces between rhombs about equal to three scale lengths 

 middorsally; on first scale row rhombs cover only one or two scale 

 lengths; a series of very small, lateral spots alternating with the 

 rhombs, these involving the lower part of the first scale row and 

 the ends of the ventrals, each spot covering an area about equal to 

 the size of three lateral scales. 



Ventral surface»of body nearly white; lateral spots encroaching 

 upon venter, but very subdued, as are all other dorsal markings where 

 they reach the venter ; ventral surface of tail white, immaculate. 



General tone of head color gray-brown ; snout light gray, stippled ; 

 this color extending in a wide band along the prefrontal suture to 

 frontal; latter band with a black border extending a little anterioi 

 to middle of prefrontals, posteriorly continuing onto corner of frontal 

 and then curving onto supraocular; area enclosed by these dark 

 borders on the frontal is dark, confluent with a dark interocular bai, 

 which is black-edged posteriorly, passes through the middle of the 

 supraocular and occupies the same position as the usual interocular 

 light bar; posterior to this a narrowly black-edged, extensive light 

 area, which occupies the posterior half of frontal, posterior portion 

 of supraoculars, and anterior half of parietals; this light area 

 notched posteriorly, the dark edge curving sharply forward nearly to 

 tip of frontal ; posterior and lateral to this is a darkly suffused area, 

 which medially extends to the anterior border of the first dorsal 

 rhomb; nuchal light collar present; its posterior border nearly 

 straight (anterior edge of first rhomb), but the collar itself very 

 dim, due to the dark dorsal suffusion; sides of head gray; posterior 

 supralabial region suffused with pink. 



Remarks. — One of the most remarkable features of this snake is the 

 peculiar head pattern, which is, in general, much like that figured 

 for tau (Taylor, op. cit.^ 1940, fig. 8), except that the dark area of 

 the frontal and parietals is light, although just as distinctly out- 

 lined ; the dorsal nuchal area, light in tau (and in all other members 

 of the upsilon group) is dark in forhesl; the interocular light bar, 

 characteristic of the entire group, is dark in forhesi. 



It appears that a pattern reversal has taken place; whether it is 

 an anomaly in the single type or is characteristic of the species can- 



