“You remember the lion of the plant-lice, the grub that eats the lice of the rosebush and, for weeks, without being able to satisfy itself, continues night and day its ferocious feasting. Well, this grub is a larva, that will change itself into a little lace-winged fly, the _hemerobius_, whose wings are of gauze and eyes of gold. Before becoming the pretty red ladybird with black spots, this pretty insect, which, in spite of its innocent air, crunches the plant-lice, is a very ugly worm, a slate-colored larva, covered with little points, and itself very fond of plant-lice. The June bug, the silly June bug, which, if its leg is held by a thread, awkwardly puffs out its wings, makes all preparations, and starts out to the tune of ‘Fly, fly, fly!’ is at first a white worm, a plump larva, fat as bacon, which lives under-ground, attacks the roots of plants, and destroys our crops. The big stag-beetle, whose head is armed with menacing mandibles shaped like the stag’s horns, is at first a large worm that lives in old tree-trunks. It is the same with the capricorn, so peculiar for its long antennæ. And the worm found in our ripe cherries, which is so repugnant to us, what does it become? It becomes a beautiful fly, its wings adorned with four bands of black velvet. And so on with others. [Illustration: Red-humped Apple Tree “Caterpillar” (_a_) moth; (_b_) caterpillar natural size] “Well, this initial state of the insect, this worm, first form of youth, is called the larva. The wonderful change which transforms the larva into a perfect insect is called metamorphosis. Caterpillars are larvæ. By metamorphosis they turn into those beautiful butterflies whose wings, decorated with the richest colors, fill us with admiration. The Argus, now so beautiful with its celestial blue wings, was first a poor hairy caterpillar; the splendid swallow-tail began by being a green caterpillar with black stripes across it and red spots on its sides. Out of these despicable vermin metamorphosis has made those delightful creatures which only the flowers can rival in elegance. “You all know the tale of Cinderella. The sisters have left for the ball, very proud, very smart. Cinderella, her heart full, is watching the kettle. The godmother arrives. ‘Go,’ says she, ‘to the garden and get a pumpkin.’ And behold, the scooped-out pumpkin changes under the godmother’s wand, into a gilded carriage. ‘Cinderella,’ says she again, ‘open the mouse-trap.’ Six mice run out of it, and are no sooner touched by the magic wand than they turn into six beautiful dappled-gray horses. A bearded rat becomes a big coachman with a commanding mustache. Six lizards sleeping behind the watering-pot become green bedizened footmen, who immediately jump up behind the carriage. Finally the poor girl’s shabby clothes are changed to gold and silver ones sprinkled with precious stones. Cinderella starts for the ball, in glass slippers. You, apparently, know the rest of it better than I.