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T. MONTICOLA, Gthr. 



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 brown 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 |3 mark on the neck. 



Nilgiris, Coimbatore. Formerly Trigonocephalus nilgi- 

 riensis. 



T. WAGLEEi, 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 j 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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