The Puss is not the only caterpillar that works up a foreign material with the contents of the spinning organs. There are several others, in fact, that use for this purpose fragments of wood or other parts of the food plants; and a still larger number bind together leaves, fresh or dead, or particles of earth or other matter. Several such cocoons will be described in our accounts of individual species in another chapter. We shall now devote a little space to a few general remarks on the chrysalides and the final metamorphosis of butterflies and moths.
CHAPTER IV
THE PUPA OR CHRYSALIS
As soon as the last moult of the caterpillar is over, the chrysalis that had already been developing under the cover of the old skin is exposed to full view; and although the perfect insect is not to be liberated for some time to come, yet some of its parts are apparently fully formed.
Fig. 30.—The Pupa of the Privet Hawk (Ligustri).
