13% 
14, 
C. macclellandi 
Scale rows 15; with inverted V-shaped mark on head... 
VIPERIDAE 
No facial pit (Viperinae) 
Facial pit present (Crotalinae) 
Top of head with large plates; 
C. kellogpi 
2 
> 
head light with brown 
markings; trunk with dark red crossbars 12-14 + 3-4... 
Azemiops feae 
Top of head with small scales or just a few large plates... 
Top of head with small, 
plates; 19-21 scale rows 
Top of head with small, 
back with 3 rows of large, 
margin and a light center 
(Vipera) 3 
smooth scales and a few large 
4 
keeled scales; 27-33 scale _ rows; 
rounded spots each with a_ dark 
Vipera russelli 
Snout blunt; rostral in contact with 2 small scales; nostril 
in center of nasal scale 
Tip of snout pointed; 
V. berus 
border of rostral in contact 
with one small scale; nostril in lower part of nasal scale.. 
Ves UiaSiema! 
Large, symmetrical plates on top of head (Agkistrodon) 6 
Small scales on top of head; 
Rostral pointing upward, 
projecting 
neck slender; head triangular.. 
(Trimeresurus) 9 
Agkistrodon acutus 
No rostral projection v/ 
Scale rows 19 A. monticola 
Scale rows 21-23 8 
Nasals long and narrow A. halys 
Nasals trapezoidal A. strauchi 
Usually green 10 
Not green 12 
Nasal with a complete suture with upper labial el 
Nasal suture with labial incomplete or absent... 
Scale rows 17; 8 upper labials 
Trimeresurus albolabris 
T. medoensis 
Scale rows 19-23; 9-11 upper labials T. stejnegeri 
Yellowish green with yellow, 
and black spots, the red 
spots forming row on center of back T. jerdoni 
Usually brown, with large, 
dark markings on back, some of 
them confluent 13 
Scale rows 19-21 i. pracalis 
Scale rows 21-29 14 
Head long, narrow; rostral narrow; nasal and internasal 
small; 14-16 small superciliaries 
Head shorter; tip of snout blunt; 
internasals; 6-8 superciliaries 
T. mucrosquamatus 
nasal large with 1-3 small 
T. monticola 
