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 Lepidoptera are greenish or brown, sometimes speckled, and occasionally ornamented with golden spots, on which account they were first called Chrysalides and Aureliæ. Many pupæ have strong angular points projecting from various parts of their bodies, and sometimes these are processes designed for a particular function. Such, for example, are the clavate appendages which project from the sides of the thorax in the pupæ of gnats, and some other dipterous 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 adminicula 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 difficulty 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
