When they are ready to come out, they do not leave their hard pupa case in the tree. They need it to protect their wings, as they creep out. When they get to the door of the hole, they pull their bodies out of the case. Then they fly off, and leave the pupa case sticking in the hole. The most useful moth, one worth all the rest, is the bombyx. He made your mother’s silk dress, and your hair ribbon. “What!” Well, did you never hear of the silk-worm? The silk-worm is the caterpillar of a moth. This is a dull, plain, little insect. Its trunk is very short, in fact, it is almost gone, for this moth never eats. It is very short-lived. All it lives for is to lay a great many hundred eggs. These eggs are laid on mulberry trees. The caterpillar soon hatches from the egg. It is a small, homely thing. It eats much during thirty days. In one thing it is different from all other caterpillars. It has a much better silk-spinner in its head. It makes a great deal of strong, yellow silk. Its body seems full of the sticky stuff, which, when it is drawn out, hardens into silk. Of this silk the caterpillar spins its cocoon. It spins hundreds of yards of fine, silk thread. Then it wraps itself in a cocoon and casts off its caterpillar skin. If left alone in the cocoon, it eats its way out, when it has become a full-grown moth. You must ask your mother or teacher to tell you how this ball of silk is turned into ribbons and dresses. From the moth which makes silk for our clothes, let us turn to the moth which eats up our fur and woollen clothes. The name of this little plague is _Tinea_. You might as well call him _tiny_, for he is the least of all moths. He looks as harmless as possible. He is a mere little silvery, fringy roll, hiding in shady places, or flitting low and silently on his little gray wings. But little Mrs. Tiny, whose name _tinea_ means that she is a spoiler of things, lays hundreds of eggs. She hides her eggs in carpets, curtains, furniture, and clothes. As soon as the little caterpillar is out of the egg, it proceeds to gnaw what it is lying on. This small creature bites and pulls out hairs, or threads, and weaves for itself a nice little rainbow case. As it grows larger, it builds more case with more threads. As these hairs or threads are stolen out of our best things, soon we find great holes in our coats and gowns. Shake the clothes, and out fall hundreds of little larvæ, or wee caterpillars. When the case is all finished the caterpillar likes to hang it up by the closed end. Then he hangs in it head downward, as a pupa. The case looks like a little roll of dust and fuzz. But the fuzzy end is the head of little _tinea_, living out his pupa days. LESSON XXVII. THE CHILD OF THE NIGHT. I suppose you have seen great cobweb-like nests, hanging on plum, cherry, and apple trees. You have heard them called “worm nests.” You have seen that they are full of brown caterpillars, about an inch long.