The wasps' nest is composed, in the interior, of fifteen or sixteen horizontal galleries, arranged in storeys, and supported by numerous pillars of separation. We give here ([Fig. 351]) a section and view of the interior, drawn from memory by Réaumur. [101] The cakes forming the combs are composed of hexagonal cells, which are always used as cradles, never as storehouses. They open below. The exterior envelope of the nest is made with leaves of a sort of greyish, very gummy paper, which is applied layer by layer. Réaumur has given a very detailed account of the way in which these insects construct their nests.[102] They collect fibres of wood—which are their raw material—make them into a sort of coarse lint, which they reduce to balls, and carry between their legs to the nest. These balls are next stuck on to the work already begun. Then the insect stretches them out, flattens them, and draws them into thin layers, as a bricklayer spreads mortar with his trowel. The wasp works with extreme quickness, always backwards, so that it may have incessantly before its eyes the work it has done: the movement of its mandibles is even quicker than that of its legs.
Towards the end of summer the nest may contain 3,000 workers, and many females, who live together in perfect harmony. The number of males exceeds that of the females. A female weighs, by herself, as much as three males or six workers. With the exception of those which are occupied in building and in taking care of the eggs, all wasps go out hunting during the day. They are carnivorous, and may be seen attacking other insects, which they tear to pieces after having killed, so as to carry the bits to their nests, where thousands of mouths are clamouring for their food. The wasp pays great attention to the vines. It penetrates also into the interior of our houses, and infests the butchers' shops; but this the butchers do not much mind, for the wasp drives away the flies which would lay their eggs on the meat and thus contribute to its corruption.
As the winter approaches, the wasps go out less and less, and very soon cease to do so at all. The greater number then die, huddled up in their nest. A few females only, as we have said, get through the cold season. They sleep with their wings and legs folded up, which gives them the appearance of chrysalides. They can nevertheless sting in this state, as M. Guérin-Méneville found out to his cost. The spring wakes them up, and they then found new colonies. "It is at this season," says M. Maurice Girard, in his book on the "Metamorphoses of Insects," "that, with a little trouble, it would be easy to diminish in a very perceptible degree the number of wasps, which are, later, so destructive to the fruit, by catching in nets the females, which might be attracted in quantities by means of the blossom of the black currant." This is a useful hint to gardeners.
The Hornets are distinguished from other wasps by their great size. They make their nests in the trunks of old trees, perforating the sound wood to arrive at the heart, which is rotten, or hollowing for themselves a hole, which they clear out by the gallery which leads to it. In this hole they construct first a dome suspended to the top by a footstalk; then a series of combs composed of cells, hanging the first to this dome, the second to the first, and so on, by stalks or pillars of a paper-like substance. When fixed under roofs, these insects have often the form of an elongated pear. [Fig. 352] represents one of these nests, after Réaumur. The societies of hornets contain fewer members than those of the common wasp; at most 200 insects.
Fig. 352.—Hanging Hornet's Nest.
The Polistes are a peculiar kind of wasp, smaller than the others, slender, with the abdomen tapering towards the base. The construction of their nests is more simple, having no envelopes, as shown in [Fig. 353]. They attach them to the stems of broom, furze, or other shrubs, by a footstalk, or pedicle. They are like little paper bouquets, composed of from twenty to thirty cells, grouped in circle.
