Butterflies and moths are the only insects that fly by means of opaque wings; but in their case the opacity is apparent rather than real, for it is caused by the presence of a very beautiful layer of coloured scales spread evenly over the outer surface of the membranes. When these scales are brushed off, membraneous wings of the ordinary transparent character are disclosed. The scales are attached to the membrane by little stems, like the quill-ends of feathers, and they are arranged in overlapping rows. The variegated colours and patterns of the insects are entirely due to them. If the wings of a butterfly be pressed upon a surface of card-board covered with gum-water to the extent of their own outlines, and be left there until the gum-water is dry, the outer layer of scales may be rubbed off with a handkerchief, and the double membranes and intervening nervures may be picked away piecemeal with a needle's point, and there will remain upon the card a most beautiful representation of the other surface of the wings, its scales being all preserved by the gum in their natural positions. If the outlines of the wings be carefully pencilled first, and the gum-water be then delicately and evenly brushed on, just as far as the outlines, a perfect and durable fac-simile, in all the original variety of colour and marking, is procured, which needs only to have the form of the body sketched in, to make it a very pretty and accurate delineation of the insect. RUSTICATION IN A FRENCH VILLAGE.