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T. MONTICOLA, Gtho\ 



Scales 23, slightly keeled. Ventrals 137-141, subc. 41. 

 Dark ash or brown, alternating dorsal series of black spots ; 

 sides black-spotted, yellow post-orbital streak ; yellow kj 

 mark on the neck, belly mottled brown. 

 Himalayas. 



T. CONVICTUS, Stolicska. 



Scales 21, keeled. Ventrals 132, subc. 29. Hardly 

 different from T. monticola ; cj mark on the neck. 



Straits. 



T. STRIGATUS, Gray. The hroiun tree-viper. 



Scales 21, keeled Ventrals 136-142. The second labial 

 does not form the front of the facial pit. No supranasals. 

 Brown, with large irregular mottled dark spots and white 

 angular JD mark on the neck. 



Nilgiris, Coimbatore. Formerly Trigonocephalus nilgi- 

 rieiisis. 



T. WAGLERi, Schlegel. 



Scales 23-25. Ventrals 139-150, subc. 42-53. The 

 second labial does not form the front of the facial pit. Head 

 scales keeled. Variable in colour ; when young, green 

 with short, reddish buff cross-bars ; the adult is black, with 

 about 35 yellow cross-bands ; yellow post-orbital streak. 



Straits. Formerly Trigonocephalus sumatranus. 



T. TRIGONOCEPHALUS, Merrem. 



Scales 17-19. Ventrals 147-152, subc. 57-63. The ante- 

 anal is notched or divided. Green, with black vertebral 

 stripe emitting alternate cross-bars ; black post-orbital and 

 head streaks ; pale green below. 

 Ceylon. 



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