COLUBRIDAE 
Key to subfamilies 
Nostril opening on side of snout 2 
Nostril opening on top of snout; right and left nasal scales 
in contact; internasal single, behind suture of nasals... 
Homalopsinae 
Mental groove present 3 
Mental groove absent Pareinae 
Subcaudals in two rows; anal plate single or divided... 
Colubrinae 
Subcaudals in single row; anal plate single..Xenoderminae 
XENODERMINAE 
Achalinus 
One pair of rostral scales, \in contact; first “pair of 
submentals in contact behind mental; no postorbital 2 
Pretrontal long, meeting “tip .of ‘nasal: first» pair - of 
submentals not in contact; first pair of infralabials in 
contact meiguensis 
Middle of body with 27 scale rows formosanus 
Middle of body with 21-25 scale rows ) 
Internasal suture shorter than prefrontal suture 4 
Internasal suture longer than prefrontal suture 5 
Midbody with 21-23 scale rows; ventrals 146-168... 
spinalis 
Midbody with 25 scale rows; ventrals 178-184... 
niger 
One temporal scale hainanus 
Two temporal scales 6 
Midbody with 21 scale rows; loreal about twice its height; 
dark brown, no middorsal stripe ater 
Midbody with 23 scale rows; loreal length about equal to its 
height; brown with a middorsal stripe rufescens 
PAREINAE 
Pareas 
Purple on back; some scales half white, half black forming 
transverse bands 2 
Brown on back; many small black spots; some spots join to 
form network 3 
Scales of back smooth (distr.: Hainan) margaritophorus 
Scales of rows 3-7 with keels macularius 
Prefrontal separated from orbit; dorsals keeled except rows 
1-2 carinatus 
Prefrontal entering orbit; dorsal almost smooth, at_~ most 
only several central rows with keels 4 
No preocular; loreal entering orbit 5 
Preocular present 6 
Ventrals 151-160; subcaudals 48-60; several middorsal scale 
rows keeled stanley 
Ventrals 175-189; subcaudals 63-69; all scale rows smooth... 
boulengeri 
Preocular broadly in contact with lower corner of eye... 
