Colour very dark olive, with a yellow zigzag line on each side from the head to the base of the tail; the angular parts enclose rhombic spaces and lateral triangles; top of head black, with a pair of undulating yellow bands from the nape to the vertex; a bright golden band round the snout; labials bright yellow; ventral shields black, paler in the middle, with yellow triangular spots at their extremities. Total length, 1,530 millimetres; tail 190. _Habitat_: Eastern Ecuador, Andes of Colombia. (11) _L. castelnaudi._--Head narrow and elongate; scales on the head smooth or feebly keeled, small; body-scales strongly keeled, in 25 or 27 rows; 230-253 ventrals; 72-83 subcaudals, all or majority in a single row. Colour greyish or brown, with dark or light-edged spots or cross-bands; head with dark spots, one of which occupies the middle of the snout; a dark band from the eye to the angle of the mouth; belly brown or blackish, spotted with yellow. Total length, 1,220 millimetres; tail 180. _Habitat_: Brazil, Ecuador, Eastern Peru. (12) _L. nummifer._--Snout broad, rounded; 10 or 11 supralabials; scales in 23-27 rows, strongly keeled; 121-134 ventrals; 26-36 subcaudals, all or the majority single. Colour pale brown, with a dorsal series of rhomboidal spots, which may form a zigzag band; belly whitish, uniform or spotted with dark brown. Total length, 800 millimetres; tail 90. _Habitat_: Mexico and Central America. (13) _L. godmani._--Snout broad, rounded; 9 or 10 supralabials; scales in 21 rows, strongly keeled; 135-142 ventrals; 22-34 subcaudals in a single row. Colour brown, with or without a dorsal series of large darker spots; belly yellowish, more or less spotted with grey or blackish. Total length, 610 millimetres; tail 60. _Habitat_: Guatemala. (14) _L. lansbergii._--Snout pointed, turned up at the end, as in Vipera aspis; scales in 25-27 rows, strongly keeled; 152-159 ventrals; 29-35 subcaudals in a single row. Colour yellowish-brown, pale brown, or grey, with a dorsal series of large rhomboidal or squarish spots, usually divided by a narrow yellow or orange vertebral line; cheeks blackish; belly powdered with brown, with or without whitish spots. Total length, 575 millimetres; tail 70. _Habitat_: from Southern Mexico to Colombia, Venezuela, and Brazil. (15) _L. brachystoma._--Similar to the foregoing species; scales in 23 (rarely 25) rows; 132-150 ventrals; 27-38 subcaudals. Total length, 500 millimetres; tail 50. _Habitat_: Southern Mexico and Central America. (16) _L. bilineatus._--Snout rounded; 7 or 8 supralabials; scales in 27-35 rows, strongly keeled; 198-218 ventrals; 59-71 subcaudals, all or majority in two rows. _Tail prehensile._ Colour green, uniform or spotted with black; a lateral yellow streak; belly white; end of tail reddish. Total length, 840 millimetres; tail 125. _Habitat_: Brazil, Bolivia, Peru, Ecuador.