The wings of the insect are, however, of a nature altogether different from the apparently analogous organs which the bird uses in flight. The wings of the bird are merely altered fore-legs. Lift up the front extremities of a quadruped, keep them asunder at their origins by bony props, fit them with freer motions and stronger muscles, and cover them with feathers, and they become wings in every essential particular. In the insect, however, the case is altogether different. The wings are not altered legs; they are superadded to the legs. The insect has its fore-legs as well as its wings. The legs all descend from the under surface of the thoracic piece, while the wings arise from its upper surface. As the wings are flapping above during flight, the unchanged legs are dangling below, in full complement. The wings are, therefore, independent and additional organs. They have no relation whatever to limbs, properly so called. But there are some other portions of the animal economy with which they do connect themselves, both by structure and function. The reader will hardly guess what those wing-allied organs are. There is a little fly, called the May-fly, which usually makes its appearance in the month of August, and which visits the districts watered by the Seine and the Marne in such abundance, that the fishermen of these rivers believe it is showered down from heaven, and accordingly call its living clouds, manna. Reaumur once saw the May-flies descend in this region like thick snow-flakes, and so fast, that the step on which he stood by the river's bank was covered by a layer four inches thick in a few minutes. The insect itself is very beautiful: it has four delicate, yellowish, lace-like wings, freckled with brown spots, and three singular hair-like projections hanging out beyond its tail. It never touches food during its mature life, but leads a short and joyous existence. It dances over the surface of the water for three or four hours, dropping its eggs as it flits, and then disappears for ever. Myriads come forth about the hour of eight in the evening; but by ten or eleven o'clock not a single straggler can be found alive.