With the piece which she has thus cut out, held in a bent position perpendicularly to her body, she flies off to her nest, and fits it into the interior with the utmost neatness and ingenuity; and, without employing any paste or glue, she trusts, as Réaumur ascertained, to the spring the leaf takes in drying, to retain it in its position. It requires from nine to ten pieces of leaf to form one cell, as they are not always of precisely the same thickness. The interior surface of each cell consists of three pieces of leaf, of equal size, narrow at one end, but gradually widening at the other, where the width equals half the length. One side of each of the pieces is the serrated margin of the leaf from which it was cut, and this margin is always placed outermost, and the cut margin innermost. Like most insects, she begins with the exterior, commencing with a layer of tapestry, which is composed of three or four oval pieces, larger in dimensions than the rest, adding a second and a third layer proportionately smaller. In forming these, she is careful not to place a joining opposite to a joining, but with all the skill of a consummate artificer, lays the middle of each piece of leaf over the margins of the others, so as by this means both to cover and strengthen the junctions. By repeating this process, she sometimes forms a fourth or a fifth layer of leaves, taking care to bend the leaves at the narrow extremity or closed end of the cell, so as to bring them into a convex shape. When she has in this manner completed a cell, her next business is to replenish it with a store of honey and pollen, which, being chiefly collected from thistles, forms a beautiful rose-coloured conserve. In this she deposits a single egg, and then covers in the opening with three pieces of leaf, so exactly circular, that a pair of compasses could not define their margin with more accuracy. In this manner the industrious and ingenious upholsterer proceeds till the whole gallery is filled, the convex extremity of the one fitting into the open end of the next, and serving both as a basis and as the means of strengthening it. If, by any accident, the labour of these insects is interrupted or the edifice deranged, they exhibit astonishing perseverance in setting it again to rights. Insects, indeed, are not easily forced to abandon any work which they may have begun.