Wasp, the common name of the hymenopterous insects of the family vespidce, of which the old genus vespa (Linn.) is the type. They are characterized by having the upper wings folded longitudinally when at rest, forming long narrow organs on the sides of the body, hence called diploptera; the tongue is moderate, the antennas long, the jaws horny and serrated, and the eyes notched or kidney-shaped; the body is usually steel-blue with yellow markings, and the abdomen, except in the males, is armed with a long, powerful, and venomous sting; the legs have no appendages as in the bees for collecting honey; their nests or vespiaries are made either under ground, or attached to the branches of trees or the -woodwork of houses. There are two groups of wasps, the social and the solitary, the common wasp of Europe (vespa vulgaris, Fabr.) and our hornets being good examples of the former, and our common mud wasp (eumenes fraterna, Say) of the latter. The social wasps live in large communities, in nests either in the ground or on trees, most of the individuals being sterile females, the neuters or workers, which in the perfect nest do most of the work as builders, soldiers, providers, and nurses; the males perform no work, though, according to the younger Huber, they keep the nest free from dirt and rubbish and carry away the bodies of those which die; the workers are winged and provided with stings, and are distinguished from the females or queens by their much smaller size.

These nests rival those of the bee in ingenuity of construction; though well provided with the means of excavating a nest, they will often make use of the deserted burrow of a field mouse to save themselves the trouble of burrowing. The nest of the social ground wasps has generally an entrance gallery about an inch in diameter and several inches long in a zigzag direction, leading to a central chamber 1 to 2 ft. in diameter when finished; for details as to the internal structure and economy of such a nest, see " Proceedings of the Boston Society of Natural History," vol. vii., pp. 411418 (November, 1860). The nest of the social tree wasp is made of paper-like material, and arranged as described under Hornet. The whole society are destroyed by cold weather, except a few young impregnated females, which pass the winter in a torpid state; each of these survivors in the ensuing spring may be seen prying into every hole in a hedge or bank to find a suitable place for a nest; having made one in the ground or on a tree, the female lays a few eggs, the larvae from which are fed by herself alone; this first brood are all workers, which on reaching their full growth relieve the queen of all labor, and by the further deposition of eggs the colony rapidly increases; the males and perfect females do not make their appearance until the end of summer; a large nest contains 300 or 400. The larvae are fleshy grubs, without feet and therefore helpless, and are fed daily by the workers, which prepare food for them in their stomachs; they are placed head downward in the cells, which are closed when they are about to pass into the nymph state.

They do not use the same nest a second season; they are remarkably attached to their young, never deserting them or abandoning the nest. The nests of the solitary wasps are made of clay or sand, and attached to walls and palings, though a few species burrow in sandy ground; they construct several cells close together, each containing a larva and a supply of living or torpid insects for its food (see Sand Wasp); in these nests there are only males and perfect females. Wasps are very voracious and omnivorous, feeding on insects, meat, fruits, honey, and other sweets; in some parts of Europe the butchers are glad to have them about their stalls- for their services in keeping off the meat flies. They sting upon the slightest provocation; the wounds are very painful, and are best treated by ammoniated lotions; they are fond of attacking bees either on the wing or in their hives, one wasp being a match for three bees, and one in its reckless daring not hesitating to attack a host of the latter; they are swift and long continuing fliers. Like the bees they are infested by hymenopterous parasites, ichneumon flies of the genus xenos (Rossi), which deposit their tiny eggs in their bodies, the larvae from which live between the rings on the back.

A few species lay up honey like the bees; a Brazilian wasp (myroptera Scutellaris, White) makes a brownish red honey, which when newly made has hardly any taste or odor; the honey of wasps, as of bees, is sometimes poisonous, and produces a kind of raving delirium. An English species (V. Britannica, Leach) suspends its fine paper-like structure from the branch of a tree, generally the silver fir. The polistes nidulans (Fabr.), of Brazil and Guiana, makes a nest of a beautiful, polished, white pasteboard, so solid as to defy the sun and rains of the tropics; it is suspended on the highest branches of the trees, swinging freely on the twig which passes through the upper part, and entirely beyond the reach of monkeys, which would otherwise destroy it in search of honey. In tropical regions the societies do not perish in winter, but the females emigrate to a distance and establish new colonies. Our common paper-making wasp is the polistes fuscata (Fabr.), of a general brown color. The common mud wasp (E. fraterna, Say) makes its cells of clay, plastering it against the outer or inner walls of houses; each cell contains a single egg, and a supply of living spiders for the young; other species use flies for the same purpose. - These ferocious and predatory insects are remarkable for the very slight stalk which unites the thoracic and abdominal regions.

As they not only destroy bees and steal honey, but injure fruit by their gnawings, farmers are generally glad to destroy them when an opportunity offers. This may be effected by hot water, sulphurous vapors, or common smoke; or the vapor of ether or chloroform may be introduced, when the nest may be dug up or stripped from the trees, and be handled with impunity.

Common Wasp (Vespa vulgaris).

Common "Wasp (Vespa vulgaris).

Nest of Polistes fuscata.

Nest of Polistes fuscata.