Fig. 347. Cocoon of the cecropia moth. It is often attached to the twig of a fruit tree.
Of all the forms in which moths and butterflies appear, the pupa is the strangest. Although we speak of this period in the life of the insect as one of rest or sleep, it is the time when the most wonderful changes take place in its body.
The queer little objects that you see illustrated in [Fig. 346] are the pupæ of the mourning-cloak butterfly. When the caterpillars were about to shed their coats for the last time, they hung themselves head downward from a twig by means of a silk button which they had spun. Then they cast off their skins, leaving the chrysalids or naked pupæ hanging; protected from birds by their spiny form and protected from many enemies, even from young naturalists, by their wood-brown color which so closely resembles the support from which they are suspended.
Fig. 348. The cecropia pupa inside the cocoon. Nearly natural size.
Let us next look at the pupa of a moth. This is often inside a covering which is called a cocoon. If you look on the fruit trees or shade trees about your home you may find a cocoon of the ce-cró-pi-a moth. You will see that it is made of silk. This covering was spun by the giant silkworm as a protection against the storms of winter. How snug the pupa is inside, and how firmly the cocoon is fastened to the twig on which you found it! [Figs. 347], [348], [349] show this interesting insect.
When you are studying pupæ remember that butterflies do not come out of cocoons. Their chrysalis or pupa is always uncovered. In the case of moths, however, the pupa is either inside a cocoon or protected by being underground or in some well sheltered place. These facts suggest a question. Is there any reason why the one should be better fitted to endure cold and storms than the other?
The Adult.
We now come to the fourth period in the lives of moths and butterflies, a period which has ever had and ever will have an interest for young and old. Since there are many persons, little and big, who cannot distinguish the two groups, butterflies and moths, let us learn the marks by which they may be known.