Page:Popular Science Monthly Volume 51.djvu/330

318 wasps and hornets of which we have any knowledge. So far as it is known to me, the Vespidœ are all social species, the individuals consisting of males, females, and neuters. They are also known as the "paper-making" wasps, having the habit of constructing paper nests of various sizes and forms in which their young are reared. Our common brown wasps (Polistes) are too well known to require any detailed description. To those living anywhere in the Atlantic States their paper nests are very familiar, being formed of a circular disk of a single tier of cells, being suspended at the solid back by a median pedicle attached to the point chosen by the community to build. Usually these cells face downward, but occasionally the plane of the nest is vertical or nearly so, causing the long axes of the cells to lie horizontally, or more or less obliquely. This grayish, papery stuff used by the paper-making wasps is a composition of their own manufacture. In the case of the common wasp it is made by the female (Vespa vulgaris), she using the fibers of old wood for the purpose. These she gnaws and kneads until they come to be of a consistence of papier-maché pulp—the mixture being assisted by the secretion of the salivary glands of the insect.

The paper hornet (Vespa maculata) builds often a very large and elaborate nest of this material. These structures are frequently found in various localities in the eastern United States and elsewhere. The year before last a colony of them built beneath the eaves of the tower to my residence in the suburban parts of Washington, D. C. A great paper nest filled the entire angle of the recess. When they build in the forests, however, these insects usually select the smaller limbs of bushes or trees, making the nest more or less spherical or ellipsoidal in contour. Sometimes these are placed high up in the trees, but again may be close to the ground. Two years ago I discovered a deserted one near my present home that was fastened to the twin trunks of a small dogwood, its lower surface being practically in contact with the ground. It was of an egg-shaped form, with the small end downward; the entire affair measuring about thirty centimetres by twenty-two centimetres, selecting for the purpose the greatest vertical diameter and the longest horizontal one (see Fig. 2). Eight distinct layers composed the walls of this nest, and its entrance, a small oval opening, was situated low down in front. It contained three tiers of unipedicled nests of cells, they being closely packed together, and the disks faced downward and were about a centimetre apart. As usual, any single cell was in contact with all its juxta-placed neighbors, and when not too closely crowded they were seen to be of a cylindrical form, but if the crowding was closer they then assumed the hexagonal shape. At their bases they were rounded, while inferiorly they were open