Adults may attain a total length of, which includes a tail long. Dorsally, T. macrolepis is bright green, with blackish skin between the scales in some places. There is a yellow or white stripe on each side of the body, which runs along the first dorsal scale row. The upper lips are pale green, and there may be a black streak behind the eye. Ventrally, it is pale greenish. The dorsal scales, which are large, keeled, and overlapping, are arranged in only 12-15 rows at midbody. The dorsal scales in the 10 middle rows are always the largest, and additional rows are made up of smaller scales. An even number of dorsal scale rows is frequently found in this species, even though it is uncommon in snakes in general. Ventrals 133-143; subcaudals divided 44-58. The scales on the top of the head are very large, smooth, and overlapping. There is an elongate subocular, which is separated from the upper labials by a row of a few small scales. There are 7-8 upper labials, of which the 3rd is the largest.
Taxonomy
Trimeresurus macrolepis has a long spineless hemipenis without papillae; the hemipenis has a long calyculate region beginning at some distance from the fork of the hemipenis and continuing until the tip. This is a characteristic similar to vipers of the Trimeresurus popeiorum group. In addition, it has enlarged head scales, somewhat akin to those of Agkistrodon species. Based on these characters, and its Western Ghats distribution, Malhotra and Thorpe resurrected the genus PeltopelorGünther, 1864 for this species. The resurrection of new genera from Trimeresurus by Malhotra & Thorpe was accepted by most subsequent authors. However, the creation of the new genera created a problem, in that the new genera did not form a distinct clade, as Trimeresurus had done and also were not distinct morphologically from one another other in the clade. Based on this view, Peltopelor has been reduced by David, Vogel & Dubois to the status of a subgenus, so that the latest taxonomic classification of this snake is Trimeresurus macrolepis.
It is both terrestrial and arboreal, using its prehensile tail to hold onto branches. It is an ambush hunting snake relying on its camouflage to catch prey. The heat-sensing loreal pits are used to locate warm-blooded prey.
Diet
It feeds mainly on frogs, lizards, small birds and rodents.
Venom
Presumed to contain hemotoxin, but not that thoroughly studied. Even though tea pickers are frequently bitten by this species, the bites are seldom fatal.
