Some days after it was finished, we cut into the post, and exposed this nest to view. It consisted of six cells of a somewhat square shape, the wood forming the lateral walls; and each was separated from the one adjacent by a partition of clay, of the thickness of a playing card. The wood was not lined with any extraneous substance, but was worked as smooth as if it had been chiseled by a joiner. There were five cells, arranged in a very singular manner--two being almost horizontal, two perpendicular, and one oblique.
The depth to which the wood was excavated in this instance was considerably less than what we have observed in other species which dig perpendicular galleries several inches deep in posts and garden-seats; and they are inferior in ingenuity to the carpentry of a bee described by Réaumur (_Xylocopa violacea_), which has not been ascertained to be a native of Britain, though a single indigenous species of the genus has been doubtingly mentioned, and is figured by Kirby and Spence, in their valuable 'Monographia.' If it ever be found here, its large size and beautiful violet-coloured wings will render mistakes impossible.
[Illustration: Cells of Carpenter-Bees, excavated in an old post.
In fig. A the cells contain the young grubs; in fig. B the cells are empty. Both figures are shown in section, and about half their natural size.]
The violet carpenter-bee usually selects an upright piece of wood, into which she bores obliquely for about an inch; and then, changing the direction, works perpendicularly, and parallel to the sides of the wood, from twelve or fifteen inches, and half an inch in breadth. Sometimes the bee is contented with one or two of these excavations; at other times, when the wood is adapted to it, she scoops out three or four--a task which sometimes requires several weeks of incessant labour.
[Illustration: A represents a part of an espalier prop, tunnelled in several places by the violet Carpenter-Bee: the stick is split, and shows the nests and passages by which they are approached. B, a portion of the prop, half the natural size. C, a piece of thin stick, pierced by the Carpenter-Bee, and split, to show the nests. D, perspective view of one of the partitions. E, Carpenter-Bee (_Xylocopa violacea_). F, Teeth of the Carpenter-Bee, greatly magnified; _a_, the upper side; _b_, the lower side.]