120 VENOMS 
Colour green, spotted with yellow ; a black streak on the temple ; 
belly greenish-yellow. 
Total length, 625 millimetres ; tail 145. 
Habitat : Guatemala. 
(c) Sistrurus. 
Head very distinct from neck, covered above with nine large 
symmetrical shields ; eyes rather small, with vertical pupils. Body 
cylindrical ; scales keeled, with apical pits; tail short, ending in 
a segmented horny apparatus (rattle), producing a special sound ; 
subcaudals all or the majority in a single row. 
(A) S. miliarius (Ground Rattle-Snake).—9—11 supralabials ; 
scales in 21 or 23 rows, strongly keeled ; 127—139 ventrals; 27—36 
subcaudals ; rattle short, consisting at the most of 10 segments. 
Colour greyish, yellowish, or brown, the vertebral line often 
orange ; two undulating dark stripes from between the eyes to the 
occiput, the enclosed space usually orange ; belly whitish, spotted 
with dark brown or black. 
Total length, 520 millimetres ; tail 70. 
Habitat: South-eastern North America, from North Carolina 
to Texas. 
(2) S. catenatus (Prairie Rattle-Snake, or Massasanga, fig. 71). 
—Two or three series of scales between the eye and the labials : 
11—14 supralabials ; scales in 23 or 25 rows; 136—153 ventrals : 
20—31 subcaudals. 
Colour the same as in 8. miliarius; a dark spot on the parietal 
shields. 
Total length, 680 millimetres; tail 80. 
Habitat: Great Lakes district; United States east of the 
Rocky Mountains and west of the Mississippi; Northern Mexico. 
(3) S. ravus.—11 or 12 supralabials ; scales in 21 or 23 rows ; 
147 ventrals ; 26 subcaudals. 
Colour yellowish-brown, with a dorsal series of dark brown 
