Part 29

These insects do not live together in societies. Indifferent neighbours, they do not lend each other mutual assistance. They have their parasites, the _Melactas_, like the humble bees. These parasites are hairy, blackish insects, spotted with white, laying their eggs in the nests of the _Anthophoras_, which permit them to do so, and, at the expense of their own progeny, bring up the intruder's little ones.

The Carpenter Bee, or Wood-piercer (_Xylocopa_), hollows out galleries in decayed wood, and builds in them cells placed one over the other--a work often occupying many weeks. She then furnishes the bottom of the cell with pollen mixed up with honey, lays an egg in the middle of this paste, and closes the cell by a ceiling of saw-dust agglutinated with saliva. On this ceiling she establishes a new cell, and so on, right up to the orifice, which she closes in the same manner. Réaumur is astonished, with reason, at the admirable instinct which makes this provident mother determine the exact quantity of nourishment which will be necessary for its larva. When this has absorbed all its provisions, it alone quite fills up its cell, and changes into a pupa. It is worthy of remark, that the head of the young is always turned downwards, in such a way that it is by the bottom of its cell that it comes out. The bottom of the first is very near the surface of the wood, so that the insect it encloses has only a thin layer of wood to pierce through in order to set itself free. Each one of those which are born next has only to pierce the floor of its hiding-place to find the road before it free. The _Xylocopæ_ pass the winter in the pupa state, and the perfect insects, with wings of a beautiful metallic violet, appear in the spring, but are not found in this country.

Other solitary bees have their hind legs unsuited for the gathering of pollen, but have the rings of the abdomen furnished with hairs for that purpose. Such are the Mason Bees of Réaumur, belonging to the genera _Osmia_ and _Chalicodoma_,[98] which build their nests against walls with tempered earth, which become very hard.

[98] At a meeting of the Entomological Society of London, Feb. 18th, 1867, Mr. Newman exhibited the lock of a door, one of several which in 1866 were found at the Kent Waterworks, Deptford, to be completely filled and choked up with nests of _Osmia Bicornis_: a portion of the nest had been forced out by the insertion of the key. The locks were in pretty constant use, so that the nests must have been built in the course of a few days.--_Journal of Proceedings of the Entomological Society of London_, 1867, lxxvi.--ED.

These nests (Figs. 340 and 341) are filled with cells of oblong form arranged irregularly. At first sight they might be taken for little lumps of earth plastered against the wall. When the perfect insect emerges, it is obliged to soften the mortar with its saliva, and to remove it, grain by grain, with its mandibles. The nests of _Chalicodomas_ are common in the environs of Paris, on walls of rough stones exposed to the south. They are often to be found in the parks of Meudon, of Conflans, of Vésinet, &c.

The Leaf-cutting Bees (_Megachile_) are not less worthy of remark in their habits. These insects make their nests in tubes lined with the leaves of the rose, the willow, the lilac, &c., placed in a cylindrical burrow. Each nest contains generally from three to six cells, separated by partitions of leaves. They cut off the pieces of leaves they require with their mandibles, the notches being wonderfully cleanly cut, as if they had been done with a punch.

They make as many as eight or ten envelopes in succession with the leaves, which, as they get dry, contract, keeping, however, the form given to them by the insect. The cells destined to receive the eggs acquire thus a certain solidity. Fig. 342 represents the nest of the Megachile.

The Upholsterer Bees (_Anthocopas_) line their nests with the petals of flowers, as, for example (_Papaver rhæas_), the corn-poppy. Their burrows are made perpendicularly in the beaten earth of roads, and each contains one solitary cell, lined with portions of petals. When the egg has been laid at the bottom of this cell, the bee fills up the rest of the hole with earth, to hide it from notice.

The Mining Bees (_Andrenæ_) hollow out in the ground tubular galleries (Fig. 343). They are not larger than ordinary flies. A great number of other bees are known, but their habits are little understood, and we shall not occupy ourselves about them.

WASPS.

Every one knows the wasps as a race of dangerous brigands which live by rapine, are incessantly fighting battles, and which exist only to do harm. However, wasps, like Figaro, are better than they are reputed to be. Their societies are admirably organised; their nests are models of industry and artistic fancy. They have even certain domestic virtues which deserve our esteem; only they are an excitable race it is well not to cross. If great heat adds to their natural irritability, they savagely attack those who annoy them, and pursue them to a distance. No one, indeed, is ignorant that their sting is very painful. In cold weather, and towards night, they are less vivacious and less to be dreaded.

The wasps are distinguished from the bees by a decided characteristic. In a state of repose they fold together their upper wings, which then seem very narrow, only spreading them out when they are about to fly; whilst the latter when at rest keep their upper wings spread out.

Wasps live in companies, which last only a year, and are composed of males, females, and workers. But the female wasp does not pass her entire life in idleness as a queen, like the mother hive bee. She occupies herself in making the nest and in taking care of the young, like the mother humble bee. The males have also their duties. They watch over the cleanliness of the habitation, and are the sanitary commissioners and undertakers to the city. These are easily recognised by their oblong bodies, having so slight a connection with the thorax, as it were by a thread.

Their sting is larger than that of the bees, and is supplied with poison from a pouch placed at its base. The males have no sting. Wasps do not secrete wax. With their mandibles they scrape wood and plants, the fragments of which they agglutinate together in such a way as to form a tough cardboard. Thus, they invented the manufacture of paper long before men. Charles de Geer, in his celebrated work, sums up the habits of these insects in the following manner:--"Wasps," says he, "are, like bees, fond of sweets and honey, although they rarely seek them in flowers; but their principal food consists in matters of quite a different kind, such as fruits of all kinds, raw flesh, and live insects, which they seize and devour. They sometimes do dreadful damage in bee-hives, devouring the honey, and killing the bees. They do not gather wax; their nests and their combs are composed of a matter resembling grey paper, which they get from rotten wood, and which they scrape off with their jaws; they make a sort of paste of these scrapings by moistening them with a certain liquid which they disgorge. The cells in the combs are hexagonal, and very regular, like those of bees."[99]

[99] "Mémoires pour servir à l'Histoire des Insectes," tome ii., p. 765. In 4to. Stockholm, 1771.

Wasps collect the materials with which they build near the place where they have chosen to establish their domicile. These materials are ligneous fibre, mixed up with saliva, with the aid of which these insects prepare the paper-like substance, which is very tough, and destined to form the walls of the cells and their exterior covering. The greater number make their habitation in the ground. Of these is our Common Wasp (_Vespa vulgaris_), which is black, agreeably contrasted with bright yellow. The Bush Wasp (_Vespa norvegica_), which inhabits woods, constructs its nest between the branches of shrubs or bushes. It is smaller than the common species. The Hornet is the largest European species of the family of the _Vespidæ_. The substance of its nest is yellowish, and very fragile, and is constructed under a roof, in a loft, or in the hole of an old wall, but most often in the hollow of a decayed tree. Another species of this family (_Polistes gallica_, Fig. 348) fixes its little nest by a footstalk to the stem of some plant.

Wasps begin laying in spring, and go on laying all the summer. Each cell receives one single egg, and, as with bees, the workers' eggs are the first laid. Eight days after the laying, there comes out of each egg a larva without feet, and already provided with two mandibles. These larvæ receive their food in the form of balls, which the females or the workers knead up with their mandibles and their legs before presenting to their nurslings, very nearly in the same way as birds give their beak full of food to their little ones. At the end of three weeks the larvæ cease to take food, and begin to shut themselves up in their cells, the interior of which they line with a coating of silk. In this they change their form, and assume the appearance of the perfect insect, with its six legs and its wings, but motionless, and contracted together. A sort of bag keeps all the organs swathed up together (Fig. 349). This pupa state lasts for eight or nine days, at the end of which time the insect is fully developed; it casts its skin, breaks the door of its prison, and launches itself into the air. A cell is no sooner abandoned than a worker visits, cleans it, and puts it in a fit state to receive another egg.

During the summer the female wasp remains constantly in the nest, absorbed with family cares. She is occupied in laying eggs and in feeding her progeny, with the active assistance of the workers, or mules, as Réaumur and Charles de Geer call them, because they are unfruitful.

In the interior of the nests you generally find the most perfectly good understanding existing, and the most perfect order, in spite of the warlike instincts of these insects. It is only on rare occasions that this domestic peace is disturbed by the quarrels of male with male or worker with worker; but these combats are not deadly. Never, moreover, has one nest of wasps been known to declare war against another for the purpose of robbing it. "The government of wasps," says M. Victor Rendu, "explains very well the gentleness of their public conduct. Amongst them there are no despots; no one either reigns or governs; each one lives at liberty in a free city, on the sole condition of never being a burden to the state. They all act in concert, without privileges or monopolies, under the influence of a common law--the great law of the public good, from which no one is exempted."[100]

[100] "L'Intelligence des Bêtes." In 18mo. Paris, 1864.

But this model republic is fatally doomed to early destruction. At the approach of winter all the workers, as also the males, perish. Some pregnant females alone hold out against the cold, and get through the winter, to propagate and perpetuate their species. Before dying, these insects destroy all the larvæ which are not hatched at the first approach of cold weather. In spring the females revive, and begin alone the construction of a new nest. They then lay workers' eggs, which are not long in furnishing them a whole regiment of devoted and active assistants. These traits are pretty nearly the same for the different species of wasps, the only difference being in the way in which they build their nests.

We have already said that the common wasp makes its nest in the ground. A gallery, of about an inch and a half in diameter, leads to the nest, situated at a depth which varies from six inches to two feet. "It is," says Réaumur, "a small subterranean town, which is not built in the style of ours, but which has a symmetry of its own. The streets and the dwelling-places are regularly distributed. It is even surrounded with walls on all sides. I do not give this name to the side of the hollow in which it is situated; the walls I allude to are only walls of paper, but strong enough, nevertheless, for the uses for which they are intended." Generally, the shape of the outside of a wasp's nest is spherical or oval, sometimes conical. Its diameter is about from twelve to sixteen inches, its surface, which resembles a mass of bivalve shells, has one hole for entrance, and another for exit, just large enough to allow of one single wasp passing in or out at the same time (Fig. 350).

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.

[101] "Mémoires," tome vi., planche 14, p. 167.

[102] _Ibid_, tome vi., p. 177.

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.

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.

The Card-making Wasp of Cayenne (_Chartergus nidulans_, Fig. 354) is a consummate artist. Its nest represents a sort of box or bag, made of a substance resembling cardboard, so fine and so white that the best worker in that material would be deceived by it. This nest has only one single hole at its base; each of the combs it contains is likewise pierced by a hole in its centre, to afford a passage to the wasps. In an architectural point of view, the card-making wasp is almost superior to the bee, for the latter does not _build_ its house, it only _furnishes_ it, as Latreille remarks with truth. The Brazilian species of _Chartergus_, which the inhabitants call Lecheguana,[103] manufactures a honey, the use of which is not without danger, as it occasions vertigo and sharp pains in the stomach. The naturalist, Auguste Saint-Hilaire, during his sojourn in Brazil, himself experienced ill effects from eating it.

[103] Hence the scientific name, _Chartergus lecheguana_.--ED.

There are, moreover, solitary wasps, which make their cells in holes which they scoop out in the ground, or in the stalks of certain plants. In the adult state these live on honey; but their larvæ are carnivorous, and the female is obliged to bring them living insects. The commonest of these solitary wasps belong to the genus _Odynerus_. This insect makes its nest in the stalk of a bramble or briar (Fig. 358) with a mortar which it prepares. The larva (Fig. 356) lines its cell with a silky cocoon. It is the last egg laid which is hatched the first; then come the others, in an inverse order from that in which they were deposited. If it had been in the other order, the insects could not have come out of the cells without destroying on their way the less advanced pupa.

ANTS.

The habits of the Ants are as remarkable as the habits of the bees. In their marvellous republics each one has his fixed duties to perform, of which he acquits himself willingly and without constraint. In consequence of their habits of foresight and frugality, ease reigns in the dwellings of these little animals, which become attached to their nest by a feeling of patriotism. Woe betide him who disturbs them in their occupations, or destroys their house! Like bees, they form a regular republic, composed--first, of males; secondly, of females; thirdly of neuters, or workers. We shall see, further on, the labours and the part played by each one of these three orders of the republic. Let us speak first of the species.

Ants are divided into a great number of species, which have been carefully described by De Geer, Latreille, and Francis Huber, the son of the celebrated blind man who wrote the history of bees. All these species have, however, some general traits in common, by which they may be easily distinguished from all other insects. Ants have a slim body on long legs. The workers are stouter and smaller than the males; and these last are smaller than the females. The males have large and prominent eyes, whilst the eyes of the workers and females are small.

Ants are provided with antennæ, bent in the form of an elbow, with which they examine everything they meet, and which seem to assist them in the communication of their ideas. Two horny, very strong mandibles serve them at the same time as pincers, tweezers, scissors, pick-axe, fork, and sword. A thin short neck joins the head to the thorax, to which, in the case of the males and females, are attached four large veiny wings. The workers only have no wings. Of the three pairs of legs, the hind ones are the longest. Each pair is armed with a spur, and fringed with very short hairs, which serve the purpose of brushes. The abdomen, large, short, oval, or square, is always most voluminous in the females.

There are three genera of ants which we shall mention. The _Myrmicæ_ have two knobs to the pedicle, by which the abdomen is attached to the thorax; the _Poneræ_ only one. In these two genera, the females and the neuters have a sting, and the larvæ do not spin a cocoon in which to change into pupa. Lastly, the _Formicæ_--ants properly so called--have but one knob on the pedicle of the abdomen, as in _Ponera_; their larvæ spin a silky cocoon. They have no sting, but they pour into the wounds made by their mandibles an acid liquor, the pungent smell of which is well known. This liquid is formic acid, a natural product, which the chemist now-a-days knows how to make artificially, by the action of dilute sulphuric acid on maize and other vegetable matters. Their whole body is impregnated with this acid, and has a strong sour smell. Some people like to chew ants, on account of their sourish taste. "They also make," says Charles de Geer, "creams for side-dishes, to which these ants give, they say, the taste of lemon-juice." We know, in the south of France, people who have eaten these _crèmes aux fourmis_! _Polyergus_ forms a sub-genus of _Formica_.

In all these species, the workers, or neuters, have the charge of the building, provisioning, and rearing of the larvæ--in fact, all the care of the household, and the defence of the nest. Deprived of wings, they are bound to the soil, and condemned to work. As compensation, to them belong strength, authority, power: nothing is done but through them. "Born protectors of an immense family still in the cradle," says M. Victor Rendu, "by their vigilance, their tenderness, and their solicitude, without being mothers themselves, they share in the duties and joy of maternity. Alone, they decide on peace or war; alone, they take part in combats: head, heart, and arm of the republic, they ensure its prosperity, watch over its defence, found colonies, and in their works show themselves great and persevering artists."