elliptical, arranged in 25-27 rows behind the neck, 25 rows at midbody, of which the 21 medial rows are 

 strongly keeled, and 17 rows before vent. Number of ventral scales: 191 and 189 in males, 190-194 

 (mean: 192) in females; anal entire; subcaudal scales: 66 and 61 pairs in males, 50-62 (mean: 57.6) in 

 females; 3 subcaudals single at the base of the tail in specimen Nr 1, and at the tip of the tail in another 

 specimen. 



Total length: male 741 + 124 mm (holotype), female 765 + 124 mm (cotype). 



Light brown above, on each side of the back 1 or 2 rows of subtriangular, dark brown, grey-edged 

 blotches alternating with one another, sometimes contiguous and giving a saw-tooth pattern or an irregular 

 stripe. Belly light grey, in males and a part of females entirely spotted with brown with the exception of the 

 neck, becoming densely powdered in the rear part of body. Head light brown above, with dark brown and 

 light gray spots and streaks; upper lips whitish, sometimes marked with a few brown spots and a 

 conspicuous, large dark brown spot under the loreal pit; a relatively wide temporal streak, wavy on its 

 lower margin and light grey on its upper margin like the canthus rostralis, running from behind the eye up 

 to the comer of the mouth; head whitish-grey below, with a few minute brown spots on infralabials in some 

 specimens. 



Biology: This species inhabits the Hengduan mountains above 3000 m. The adult snakes were found 

 either in bushes or among grasses, or in wet places in forest, or in riparian areas along small streams. Two 

 specimens were collected in a stone pile close to dwellings, one was caught inside a house. The air 

 temperature was quite low when these snakes were found and these places were probably hibernation sites. 

 Two juveniles were collected on banks of a river and a stream. 



