194 MAJOR F. WALL, I.M.S., C.M.Z.S. 
KEY T0 THE GENUS Distira. 
A. Veutrals present; anterior three to four times breadth of last costal row. 
(See fig. 57) 
B. Ventrals present; anterior not more than twice breadth of last costal row. 
(See fig. 38). 
(a) Seales in midbody 1g to 21 
(b) Scales in midbody more than 21. 
(a') Ventrals with median suture or furrow in posterior half of body. 
(See fig. 13). 
(a2) Prefrontal touches second supralabial, but uot third. 
Anterior costals 17 to 21. Ventrals 225 to 208 
(Bb) Prefrontal touches third supralabial (rarely second also), 
Anterior costals 21T to 25. Ventrals 377 to 474 
(b'!) Ventrais unfurrowed; a few posterior irregularly divided, es- 
pecially about umbilical sear. 
(a) Posterior costals juxtaposed (except rare examples of fasctata 
and some forquata). 
(a?) One or more marginals. 
(a+) One large anterior temporal. 
(a®) Anterior costals 1 to g less than posterior .. 
(b*) Anterior costals 10 to 22 less than posterior 
(04) Two small superposed anterior temporals. 
(a') Anterior costals 25 to 29 as 
(b®) Anterior costals 31 to 37; parietals touching 
postocular : 
(c’) Anterior costals 36 to 45: parietals not 
touching postocular pC 
(6°) No marginals. 
(a) Anterior costals 29 to 41 
(b*) Anterior costals 45 
(0?) Posterior costals imbricate or sub-imbricate (except rare 
examples of cerulescens and some torquata). 
(a*) Anterior costals 19 to 23. Neck 4} to 4 greatest body 
depth y: = 
(0°) Anterior costals 23 or more. Neck } to } greatest 
body depth. 
(a) Ventrals 250 or less 
(b') Ventrals 270 to 375. 
(a°) Costals in midbody 29 to 36. One large 
anterior temporal. Praefrontal touching 
2nd labial re be 
(b°) Costals in midbody 33 to 44. ‘Two super- 
posed anterior temporals. Prefrontal 
touching 2nd labial 
viperina. 
jerdont. 
gracilis. 
cantorts. 
torquata. 
fasciata. 
mamillaris. 
lapemoides. 
ceerulescens. 
ornata. 
ocellata. 
obscura. 
major. 
spiralis. 
cyanocincta. 
