ENTOMOLOGY. 
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it bears insulated spines; and not unfrequently it 
is tubercular. The colour of the kinds that are 
little exposed, from their situation, to the action of 
light, is generally yellowish white ; many of those, 
however, which are concealed beneath the earth, 
are light-brown ; most of those belonging to the Lep- 
Idoptera are greenish or brown, sometimes speckled, 
and occasionally ornamented with golden spots, on 
which account they were first called Chrysalides and 
Aurelise. Many pupae have strong angular points 
projecting from various parts of their bodies, and 
sometimes these are processes designed for a par- 
ticular function. Such, for example, are the clavate 
appendages which project from the sides of the 
thorax in the pupae of gnats, and some other dipter- 
ous species which live in the water. The dorsal 
segments of many are armed with sharp serratures 
looking towards the anus, which serve an important 
purpose in their economy, for it is by their means 
the pupa works its way to the surface of the ground, 
when the perfect insect is about to be disclosed. 
When the segments are curved, the convex side, by 
means of these spines (called adminicida by Kirby), 
finds a point d‘ appui higher up than it occupied 
formerly, and when it has attained this elevation, 
another curvature of the abdomen enables it to 
gain another step. In this way they have no diffi- 
culty in rising to the surface merely by wriggling 
the abdomen from side to side. This structure is 
well exemplified in the large pupa of the goat moth, a 
highly magnified view of whose serrated dorsal ridges 
