MORPHOLOGY OF VENOMOUS SNAKES 39 



Lachesis lansbergii. 



Snout turned up somewhat as in Vipera aspis. Subcaudals in one row. Length 

 2 feet. Southern Mexico, Colombia, Venezuela, Brazil. 

 Lachesis brachystoma. 



Snout turned up. Length 1.5 feet. Southern Mexico and Central America. 



Lachesis bilineatus. 



Snout rounded; subcaudals for most part in two rows. Tail prehensile. Color 

 greenish, in contrast to most of the enumerated species, which are mostly brownish, 

 grayish, or dark yellowish, with or without black speckles; belly white; end of 

 tail red. Length 2.5 feet. Brazil, Bolivia, Peru, Ecuador. 

 Lachesis undulattis. 



Snout short and round. Color olive or brown, sometimes with black speckles. 

 Tail prehensile. Length about 2 feet. Mexico. 

 Lachesis lateralis. 



Snout rounded, subcaudals in one row. Tail prehensile. Color greenish with 

 yellow line on each side. Length 1.6 feet. Costa Rica. 



Lachesis bicolor. 



Much like foregoing. Green with yellow belly. Length 1.2 feet. Guatemala. 



Lachesis schlegelii. 



Subcaudals in one row. Tail prehensile. Coloration very variable: Green is 

 predominant, with speckles or bands of black, rose, or red; belly yellow, with green 

 or red; end of tail red. Length 2 feet. Central America, Colombia, Ecuador. 

 Lachesis nigroviridis. 



Subcaudals in one row. Tail prehensile. Color greenish or olive with black 

 speckles; belly yellow; head black. Length 1.6 feet. Costa Rica. 

 Lachesis aurifer. 



Snout short and rounded; subcaudal in one row. Tail prehensile. Color green 

 with yellow speckles; black band on temple. Belly greenish-yellow. Length about 

 2.5 feet. Guatemala. 



The Asiatic representatives of Lachesis are characterized by the shorter tail, 

 which is often prehensile and enables the snake to climb or grasp the trees during 

 the hunt for its prey. The subcaudals are in two rows. On account of the more 

 general characteristics peculiar to this group, these snakes, though undoubtedly 

 belonging to the common genus Lachesis, are divided into two main groups. As 

 was mentioned previously, the term Trimeresurus is used by Stejneger in lieu of 

 Lachesis, because the character of the tail is considered by him to be sufficient 

 reason to group the Asiatic pit-vipers under the former designation. 



A . The first supralahial scale is in contact with its neighbor. 



L Scales in 21 to 25 (seldom 27) rows; 129 to 158 ventrals; 21 to 

 27 subcaudals; 5 to 9 series of scales between supraocular 

 plates. Tail non-prehensile. 

 Lachesis monticola. 



Snout obtuse. Color brown or yellow above, pale yellow or brown on sides, 

 with a brown temporal band; belly white, with brown spots. Length 2.5 feet. 

 Tibet, Himalaya (up to 7,500 feet), Burma, Malay Peninsula, Singapore, Sumatra. 



Lachesis okinavensis. 



Trimeresurus okinavensis. 



End of snout pointed and raised. Color brown above with dark crossbands and 

 a light temporal band ; belly brown with black spots, especially along side of body. 

 Length about 1.25 feet. Okinawa, Riu Kiu Islands, Japan. 



