60 SYNOPSES AND DESCRIPTIONS. 



Postmaxillary teeth larger, separated by an interspace ; 



rostral trihedral, sharp-angled Heterodon. 



Postmaxillary teeth longer, smooth ; 



rostral swollen, rounded Cemophora. 



eye large, pupil round Xenodon. 



eye small, pupil subelliptical Hypsiglena. 



Tachymenis. 



Wiegmann, 1834. 



Moderately stout to slender ; belly broad, rounded ; head distinct from 

 the neck, narrow in front ; tail moderate, tapering. Eye moderate, pupil 

 round or subcircular. Posterior maxillary teeth longer, grooved; anterior 

 equal or slightly longer than those immediately following. Loreal present 

 or united with other shields. Crown-shields nine. Internasals somewhat 

 narrow in front. Oculars 1 — 2. Scales smooth, in 17 to -21 rows. Anal 

 bifid. 

 Labials seven ; scales in 19 series ; 



longitudinal bands, continued on the head lineata. 



ending at the back of the head iniperialis. 

 vermilion, shading through orange to the golden beneath 



later itia. 

 a dark band with white borders on each side of the neck 



proterops. 

 Labials eight; scales in 21 (19 — 21) rows; 



a white band on each side of the anterior part of the trunk 



jissklens. 

 brown, with an indistinct dorsal streak 



bipunctata. 

 head and neck brown; behind this a yellowish neck band of about 

 four Scales in width melanocephala. 



Several of these species can hardly be regarded as firmly established. 

 The descriptions are insufficient for comparison. 



Tachymenis lineata. 



Tomodon lineatus Dumeril & Bibrcm, 1854, Erp. Gen. VII, 936, pi. 73. 



Head distinct from the neck ; tail near one fourth of the total. Posterior 

 upper maxillary teeth longer, grooved. Crown-shields normal. Rostral 



