52 VENOMS 
They are characterised by a triangular head, covered with small 
scales or small shields, and by a cylindrical or compressed body. 
The Asiatic species have the subcaudal scales in two rows and the 
tail short, and often prehensile, which enables them to climb trees 
or bushes, where they lie in wait for their prey. 
Their classification is based upon the following characters :— 
A. First infralabial scale in contact with its fellow. 
158 ventrals ; 21— 
57 subcaudals; 5—9 series of scales between the supraocular 
I. Scales in 21—25 (rarely 27) rows; 129 
shields; tail non-prehensile. 
Fic. 32.—Lachesis okinavensis. (After G. A. Boulenger, op. cit.) 
(1) L. monticola.—Supraocular shields large, separated by 5—8 
scales ; snout obtuse. 
Colour brown or yellowish above, brown or pale yellow on the 
sides, with a brown temporal streak. Belly white, spotted with 
brown. 
Total length, 740 millimetres; tail 115. 
Habitat: Tibet, Himalayas (2,000 to 8,000 feet), Hills of Assam, 
Burma, Malay Peninsula, Singapore, Sumatra. 
(2) L. okinavensis (fig. 32).—Supraocular shields large, separ- 
