140 Life and Immortality. 
difference is manifest in the coloration. In from three to 
five days the caterpillar has again changed its skin, doubled 
its length, assumed more pronounced colors, which are 
diversified in some with mottlings upon back and sides, and 
developed along the back, from the third to the tenth joint, 
a low, broad, continuous, tuberculous ridge, cleft to the 
body at the junction of the segments, the anterior edge of 
each joint being depressed, the sides incurved. The third 
moult takes place in three or four days more, but there is 
very little change from the former period. Three or four 
days subsequent to this change occurs the fourth or final 
moult, and in five or six days from this the larva is ready to 
pass into the chrysalis state. 
In its mature form the larva is about one-half of an inch 
in length. The body is onisciform, flattened at base, fur- 
nished with retractile legs, and has the back elevated into a 
rounded ridge, which slopes backwards from the sixth seg- 
ment. The sides are rather deeply hollowed, and in the 
middle of each segment, from the third to the eleventh, is a 
vertical, narrow depression. The last segments are flattened, 
the last of all terminating roundly, its sides being narrowed 
and slightly incurved, while the second segment is flattened, 
arched and bent nearly flat over the head. Standing on the 
body is a ridge, tubercular in nature, which in each segment 
from the third to the eleventh is distinct and cleft to the 
body. In color, specimens vary. Some examples are white, 
others decidedly greenish, but many have the posterior slope 
of the second segment black or dark brown, while a few have 
most of the back a dark brown, irregularly mottling a light 
ground, or with small brown patches diffused over the back, 
but mostly on the anterior segments. The entire surface is 
velvety. This appearance is caused by minute stellate glossy 
processes, scarcely raised above the surface, mostly six-rayed, 
and sending from the centre a concolored filamentous spine 
a little longer than the rays. These stars are arranged in 
nearly regular rows, and are light, except in the brown 
