III.HEMIPTERA.The Hemiptera are particularly distinguished from other kinds of insects by the form of their mouth, which consists of a beak, more or less long, composed of six parts: that is, of a lower lip, or sheath; four internal threads, representing the mandibles and jaws of the grinding insects, and which are the perforating parts of the beaks; and, lastly, of the upper lip or labrum. Owing to this apparatus, these insects are essentially sucking ones, and chiefly nourish themselves with the juices of vegetables, which they draw up with their beak. The wings of the Hemiptera are usually four in number; in some species they are membranous and similar to each other, and in others the upper are of rather harder consistency than the lower ones. In general, the former are quite different from the lower wings, and are only membranous at the tip, whereas the other part is thick, tough, and coriaceous.The Hemiptera are divided into two very distinct sections. The one is composed of insects whose beak grows from the forehead or upper part of the head, and whose anterior wings are half coriaceous and half membranous, having the base of a different texture from the extremity: these are the Heteroptera (ἑτερος, different; πτερον, wing). The other section is composed of those whose beak grows from the lower part of the head, and whose anterior wings are always of the same consistency throughout: these are the Homoptera (ὁμος, the same; πτερον, wing). We are about to give the history of these two sub-orders.Heteroptera.The insects formerly known by the general name of Bugs have been divided by Latreille into two large families, containing: the one theGeocorisæ,[19]or Land Bugs; the other theHydrocorisæ,[20]or Water Bugs.The land bugs consist of a great number of kinds, which, for the most part, are of little interest. We will only mention here thePeniatomidæ, commonly known as Wood Bugs; theLygæi, Bugs, properly so called; theReduvii, and theHydrometræ.ThePentatomidæ, which comprise many genera, include the wood bugs of most authors. They are to be found on plants and trees. They fly quickly, but only for a short time.Fig. 69.—Grey Pentatoma (Raphigaster griseus).Fig. 69.Grey Pentatoma(Raphigaster griseus).The Ornamented Pentatoma (Strachia[Pentatoma]ornata), known as the Red Cabbage Bug, is very commonly found on the cabbage, and on most of the cruciferous plants. It is variegated with red and black, and its colours are subject to numerous variations. The Grey Pentatoma (Raphigaster griseus),Fig. 69, is common throughout the whole of Europe. In autumn these bugs are frequently to be found on raspberries, to which they impart their disagreeable smell. They are also to be found in quantities on the mullein, when that plant is in flower. The upper parts of the head are of a greyish brown, and are sometimes slightly purple. The coriaceous part of the hemelytra is of a purple tint, but the membranous part is brown. All these parts are covered with black spots, which are only to be seen with a magnifying-glass. The wings are blackish. The under part of the whole body and the feet are of a light and rather yellowish grey, with a considerable number of small black spots. The abdomen is black above; and it is bordered with alternate black and white spots.We have repeated here the description given of this bug by the illustrious Swedish naturalist, De Geer, because our young readers have most likely met with this insect, or will do so some day when gathering raspberries.The Grey Pentatoma, marked with black, yellow, and red, is to be found throughout the whole of Europe in cultivated fields and gardens, sometimes also on the trunks of large trees, especially elms. This species, in common with the greater part of those which compose the group we are describing, emits a smell when irritated or menaced by some danger. At other times no odour will be noticed. Let us hear what M. Léon Dufour says on this subject."Seize the Pentatoma with a pair of pincers and plunge it into a glass of clear water; look through a magnifying-glass, and you will see innumerable small globules arising from its body, which, bursting on the surface of the water, exhale that odour which is so disagreeable. This vapour, which is essentially acrid, if it happensto touch the eyes, causes a considerable amount of irritation. If one of these insects is held between the fingers, so as not to stop up the odoriferous orifices, and to cause this vapour to touch a part of the skin, a spot, either brown or livid, will ensue on that part, which lotions, though repeatedly applied, will at first fail to remove, and which produces in the cutaneous tissue an alteration similar to that which succeeds the application of mineral acids."The disagreeable smell exhaled by different species of Pentatoma is the result of a fluid secreted by a single pear-shaped gland, either red or yellow, which occupies the centre of the thorax, and which terminates between the hind legs.With theSyromastes, which are bugs of this same section, the secretion has, on the contrary, an agreeable smell, which reminds one of that of apples. Many kinds of Pentatoma are destructive to agriculture. Others, however, attack the destructive insects, and ought therefore to be carefully spared. We will mention in this case the Blue Pentatoma, which kills theAltica[21]of the vine.There may be observed, at the foot and about the lower part of trees, or at the base of walls exposed to the mid-day sun, groups of fifty or sixty small insects pressed close to each other, and often one on the top of the other, their heads in the direction of a centre point. They are red, spotted with black. In the neighbourhood of Paris the children call them "Suisses," probably on account of the red on their bodies, that being the colour of the uniform of the Swiss troops formerly in the service of France. In Burgundy the children call them "petits cochons rouges." They will be found described in Geoffroy's "Histoire des Insectes," under the name of the Red Garden Bug. At the present day they are placed in the genusLygæus.[22]When the bad weather comes, these little "Suisses" take refuge under stones and the bark of trees to pass the winter. During the whole of that season they remain in a sort of torpid state. But in the first days of spring they revive, and resume their ordinary habits. They suck the sap of vegetables, piercing the capsules of divers kinds of mallows, and always keeping in the sunshine.Fig. 70.—Bed Bug (Acanthia lectularia), magnified.Fig. 70.Bed Bug (Acanthia lectularia),magnified.Fig. 71.—Egg of Bug, magnified.Fig. 71.Egg of Bug, magnified.The Bug, popularly so called, or Bed Bug (Acanthia lectularia, orCimex lectularius,Fig. 70), a most disagreeable and stinking insect, abounds in dirty houses, principally in towns, and above all in those of warm countries. It lives in beds, in wood-work, and paper-hangings. There is no crack, however narrow it may be, into which it is unable to slip. It is nocturnal, shunning the light. "Nocturnumfœtidum animal," says Linnæus. Its body is oval, about the fifth of an inch in length, flat, soft, of a brown colour, and covered with little hairs. Its head is provided with two hairy antennæ, and two round black eyes, and has a short beak, curved directly under its thorax, and lying in a shallow groove when the animal is at rest. This beak, composed of three joints, contains four thin, straight, and sharp hairs. The thorax is dilated at the sides. The abdomen is very much developed, orbicular, composed of eight segments, very much depressed, and easily crushed by the fingers. The hemelytra are rudimentary. It has no membranous wings. The tarsi have three articulations, of which the last is provided with two strong hooks."These animals," says Moquin-Tandon, in his "Zoologie Médicale," "do not draw up the sanguineous fluid by suction, properly so-called, as leeches do. The organisation of their buccal apparatus does not allow of this. The hairs of the beak applied the one against the other exercise a sort of alternate motion, which draws the blood up into the œsophagus, very much in the same manner as water rises in a chain pump. This rising is assisted by the viscous nature of the fluid, and above all, by the globules it contains." The part of the skin which the Bug has pierced, producing a painful sensation, is easily recognised by a little reddish mark, presenting in its centre a dark spot. Generally a little blister rises on the point pierced, and sometimes, if the Bug-bites are numerous, these blisters become confluent, and resemble a sort of eruption. These disgusting insects lay, towards the month of May, oblong whitish eggs (Fig. 71), having a small aperture, through which the larva comes out. The larva differs from the insect in its perfect state, in its colour, which is pale or yellowish. This insect exists in nearly the whole of Europe, although it is rare or almost unknown in the northern parts. The towns of central Europe are the most infested by this parasite, but those of the north are not completely free from its presence. The Marquis de Custine assures us that at St. Petersburg he found them numerous. It is found also in Scotland; is very rare in the south of Europe; and seldom seen in Italy, where it is, however, replaced by other insects more dangerous or more annoying.It has been said that the Bug was brought into Europe from America; but Aristotle, Pliny, and Dioscorides mention its existence. It is certain that it was unknown in England till the beginning of the sixteenth century. A celebrated traveller, a Spanish naturalist, Azara, has remarked that the Bug does not infest man in his savage state, but only when congregated together in a state of civilisation, and in houses, as in Europe. From this he concluded that the Bug was not created till long after man, when, after many centuries had elapsed since his appearance on the globe, men formed themselves into societies, into republics, or little states.The bug is not a gluttonous insect, always bloodthirsty; on the contrary, its sobriety is remarkable. It is only after a prolonged fast that it bites animals; and Audouin has stated that it can live a year and even two years without food.From time immemorial a number of different means have been employed for destroying these insects; but in spite of all, nothing is more difficult than to get rid of them from wood-work and paper-hangings, when they have once infested them. In general, strong odours cause their death. And so, to rid oneself of these disagreeable guests, it has been recommended to use tobacco smoke, essence of turpentine, the fumes of sulphur, &c. Mercurial ointment and corrosive sublimate are also excellent means for their destruction; and for the same purpose the merits of a plant belonging to the order Cruciferæ,Lepidium ruderale, have been much vaunted; and more recently still, the root of the Pyrethrum, a species of camomile, reduced to powder, and blown into the furniture or wood-work. This powder is known and employed at Paris under the name of "poudre insecticide."There are two other kinds of bugs (Acanthia) which attack men. The one is theAcanthia ciliata, which has been found in the houses of Kazan, and which differs from the bed bug not only in its form, but also in its habits. It does not live in companies, in the narrow cracks of furniture, but moves about alone, at a slow pace, over walls or the counterpanes of beds. Its beak is very long, and its bite is very painful, and produces obstinate swellings.The other species is theAcanthia rotundata, which is found in the Island of La Réunion, and attacks men in the same way as does the European bug. Two species of the same genus live as parasites on swallows and domestic pigeons. There is another species, which is peculiar to the bats of our climates.TheReduvius personatus, called also Fly Bug, by Geoffroy, the old historian of the insects of the environs of Paris, is commonenough in France. It keeps to the houses, and is found especially near ovens and chimney-pieces. It is about three-quarters of an inch in length, oblong, flat on its upper side, brownish, has horizontal hemelytra crossed over each other, and very fully developed wings, which serve for flight. Its head, narrow, supported by a well-defined neck, is provided with two composite and two simple eyes. It requires, no doubt, to see very clearly, as it flies by night. It should not be caught without great caution. If you desire to examine it closely, when, in the hottest part of the summer, it comes in the evening and flutters round the lights, you must be careful how you seize it, for it wounds. The wounds inflicted by it are very painful—more painful than those of the bee—and they immediately cause a numbness.As theReduviuskills different insects very rapidly, by piercing them with its long beak, it is probable that it secretes some kind of venom. But as yet the organ that produces this poison has not been discovered. However that may be, its beak is curved, and about the tenth of an inch long, the surface bristling with hairs. It is composed of three joints, and contains four stiff, lanceolate, and very pointed squamose hairs.This insect often seeks its prey in places where spiders spin their webs. When they walk on, or are caught in, the spiders' webs, the spiders take care not to seize them, for they fear their beak. They prudently allow them to struggle about the nets, where they very soon die of hunger. TheReduviusis often seen, either a prisoner or dead, in the midst of a spider's web."This bug," says Charles de Geer, "has, in the pupal condition, or before its wings are developed, an appearance altogether hideous and revolting. One would take it, at the first glance, for one of the ugliest of spiders. That which above all renders it so disagreeable to the sight is that it is entirely covered, and, as it were, enveloped with a greyish matter, which is nothing else but the dust which one sees in the corners of badly-swept rooms, and which is generally mixed with sand and particles of wool, or silk, or other similar matters which come from furniture and clothes, rendering the legs of this insect thick and deformed, and giving to its whole body a very singular appearance."What instincts! what habits! Under this borrowed costume, under this cloak, which is no part of itself, the insect, as it were, masked, has become twice its real size. What becomes of its disguise, and how does it manage to walk? Of what use to it is this dirty and grotesque fancy dress?Let us listen to De Geer. "It walks as fast, when it likes, as other bugs; but generally its walk is slow, and it moves with measured steps. After having taken one step forward, it stops a while, and then takes another, leaving, at each movement, the opposite leg in repose; it goes on thus continually, step after step in succession, which gives it the appearance of walking as if by jerks, and in measure. It makes almost the same sort of movement with its antennæ, which it moves also at intervals and by jerks. All these movements have a more singular appearance than it is possible for us to describe."[23]By means of this disguise, it can approach little animals, which become its prey, such as flies, spiders, bed bugs.Fig. 72.—Pupa of Reduvius personatus, covered with its cloak of dust (magnified).Fig. 73.—Pupa of Reduvius personatus, denuded of its cloak of dust (magnified).Fig. 72.—Pupa of Reduvius personatus, covered with its cloak of dust (magnified).Fig. 73.—Pupa of Reduvius personatus, denuded of its cloak of dust (magnified).To see what a curious appearance theReduviuspresents, one should take off its borrowed costume. Then you will observe an entirely different animal, and one which has nothing repulsive about it. With the exception of the hemelytra and wings, which it has not yet got, all its parts have the form which they are to have later, after the wings are developed.Fig. 72 represents, from Charles de Geer's Memoir, the pupa of theReduvius personatuscovered with dust, and resembling a spider;Fig. 73the same insect cleaned, freed from the cloak of dust which served to disguise it.Fig. 74.—Hydrometra stagnorum.TheHydrometræ(from ὑδωρ, water, and μετρειν, to measure)have linear bodies. The head, which forms nearly the third of the entire length, is furnished with two long antennæ, and armed with a thin, hair-like beak. The legs are long, and of equal length. The reader may have often seen theHydrometra stagnorumwalking by jerks on the surface of the water (Fig. 74). The body and legs are of a ferruginous colour, the hemelytra a dull brown, and the wings hyaline, or glassy, and slightly blackish. Geoffroy says that it resembles a long needle, and calls it the Needle Bug.TheHydrocorisæ, or Water Bugs, have the antennæ shorter than the head, or scarcely attaining to its length, and inserted and hidden under the eyes, which are in general of remarkable size. All these Hemiptera are aquatic and carnivorous. We will mention the two principal types, theNepæ, or Water Scorpions, and theNotonectæ, or Boatmen.Fig. 75.—Nepa cinerea.TheNepa cinerea(Fig. 75), which Geoffroy calls the Oval-bodied Water Scorpion, and which he also designates by the name of the Water Spider, is very common in the stagnant waters of ponds and ditches. Its body, oval, very flat, of an ashy colour, with red on the abdomen, is four-fifths of an inch long. The hemelytra are horizontal, coriaceous, and of a dirty grey colour. Its front legs, with short haunches, and very broad thighs, are terminated by strong pincers, which give to the insect a strong resemblance to the scorpion. It is by folding back the leg and the tarsus under the thigh, that the animal holds its prey, and sucks it with its rostrum or beak.This rostrum is composed of three joints, and contains four pointed bristles. Two present on one side a sort of narrow sharp blade, and have teeth towards their base. Of the two others, the one is a thin smooth needle, the other is provided with hairs directed backwards and forwards.It is with this rostrum, which resembles a case of surgical instruments, that theNepapierces and sucks little aquatic insects, not even sparing its own species. Its wound is painful to man, but not in the least dangerous. With its four hind legs theNepaswims, but at a very slow pace. It generally drags itself along the bottom of thewater, on the mud, and does not avoid the hand put out to seize it. Its body is terminated by a tail, composed of two grooved threads, which, when applied together, form a tube, capable of being moved from side to side. Through this canal it breathes the outer air; it puts the end of it out of the water, and the air enters it by inspiration. Some very small hairs, with which the interiors of the grooves are lined, interlace each other, and prevent the water from penetrating into the canal. It is probable that this same canal serves also for depositing the eggs. These last resemble small seeds, covered with points, and are buried in the stalks of aquatic plants.Next to theNepacomes theRanatra, with a cylindrical, elongated, linear body, with very long and very thin hind legs, and of which one species, which Geoffroy calls the "aquatic scorpion with an elongated body," is common everywhere in stagnant waters in spring. It is brownish, carnivorous, and very voracious.Fig. 76.—Corixa striata.We must now mention the genusCorixa, of which one species, theCorixa striata, is very common. This insect walks badly and slowly on land, but swims and cuts through the water with a prodigious rapidity.However, it is not to delay over this last species that we have here mentioned the name of this genus. Some insects which belong to it, and which are found in Mexico, deserve to be alluded to, on account of certain peculiarities which their eggs present. A naturalist, M. Virlet d'Aoust, has published the following details on this subject:—"Thousands of small amphibious flies," he says, "flit about in the air on the surface of lakes, and diving down into the water many feet, and even many fathoms, go to the bottom to lay their eggs, and only emerge from the water probably to die close by. We were fortunate enough to be present at a great fishing or harvest of the eggs, which, under the Mexican name ofhautle(haoutle), serve for food to the Indians, who seem to be no less fond of them than the Chinese are of their swallows' nests, which they resemble somewhat in taste; only thehautleis far from commanding such high prices as the Chinese pay for their birds' nests, which for that reason are reserved entirely for the tables of the rich; while, for a few smallcoins, we were able to carry away with us about a bushel of thehautle, a portion of which, at our request, Mme. B—— was kind enough to prepare for us."They dress these in different ways, but generally make a sort of cake, which is served up with a sauce, to which the Mexicans give a zest, as they do indeed to all their dishes, by adding to itchilié, which is composed of green pimento crushed. This is how the natives proceed when they are fishing forhautle: they form with reeds bent together a sort of fasces, which they place vertically in the lake at some distance from the bank, and as these are bound together by one of the reeds, the ends of which are so arranged as to form an indicating buoy, it is easy to draw them out at will. Twelve to fifteen days suffice for each reed in these fasces to be entirely covered with eggs, which they thus fish up by millions. The former are then left to dry in the sun, on a cloth, for an hour or more; the grains are then easily detached. After this operation, they are replaced in the water for the next hautle harvest."M. Virlet had attributed to flies the eggs of which we have been speaking. But in 1851 M. Guérin-Méneville having received, transmitted to him by M. Ghiliani, eggs of whichhautleis made, and some of the insects said to produce them, stated that the latter belonged to two different species. The one had been known a long time since under the name ofCorixa mercenaria; M. Guérin-Méneville called the otherCorixa femorata.The same entomologist discovered, among the eggs of these two species, other eggs of a more considerable size, and which he attributed to a new species of the genusNotonecta, about which we are now going to say a few words.TheNotonecta glauca, which Geoffroy calls the Large Bug with Oars ("Grande punaise à avirons"), is very common in ditches, reservoirs, and stagnant waters. Its body is oblong, narrow, contracted posteriorly, convex above, flat below, having, at its sides and its extremities, hairs which, when spread out, support the animal on the water. Its head is large and of a slightly greenish grey, and has on each of its sides a very large eye of a pale brown colour. Its thorax is greyish, the hemelytra of a greenish grey, the membranous wings white. Of its legs, the front four are short; but the hind legs, almost twice as long, are furnished with long hairs, and resemble oars. It is with the aid of these that the animal moves through the water; and it does so in a singular manner, placing itself on its back, and generally in an inclined position, as inFig. 77.When this insect, on the contrary, drags itself along on the mud,the front legs are those which it employs, the hind legs being idle, and merely drawn along behind it. It is generally towards the evening or during the night that it comes out of the water, to walk and to fly, if it wishes to pass from one marsh to another.Fig. 77.—Notonecta glauca.This bloodthirsty insect lives entirely by rapine; it is one of the most carnivorous of insects. Those which it attacks die very soon after they have been hurt by it. De Geer thinks that the water bug drops into the wound a poisonous humour. It seizes upon insects much bigger, and apparently much stronger, than itself, and does not spare its own species.The instrument with which theNotonectaattacks its prey is composed of a very strong and very long conical beak, formed of four joints. The sucker is composed of an upper piece, short and pointed, and of four fine pointed hairs.The female of theNotonecta glaucalays a great number of eggs, white, and of elongated shape, which it deposits on the stems and leaves of aquatic plants. The eggs are hatched at the beginning of spring, or in May, and the young ones at once begin to swim about like their mother, on their backs, belly upwards. M. Léon Dufour says on this subject:—"A dorsal region, raised like a donkey's back, or like the rounded keel of a boat, and covered with a velvety substance, which renders it impermeable, numerous fine fringes which garnish either the hind legs, or the borders of the abdomen and thorax, or lastly in a double row form a crest or comb running down the surface of the belly, and which spread themselves out or fold themselves in at the will of the insect, just like fins, favour both this supine attitude and the accuracy of the swimming movements of theNotonectæ. Since Nature—which seems often to delight in producing extraordinary exceptions to her ordinary rules, thus bearing witness to the immensity of her resources—had condemned this animal to pass its life in an inverted position, it was necessary, for the maintenance of its existence, that it should provide it with an organisation in harmony with this attitude. It is also for this object that its head is bent over its chest; that its eyes, of an oval shape, can see below from above; that the front as well as the middle legs, agile and curved, solely destined for prehension, canto a certain extent become unbent by means of the elongated haunches which fix them to the body, and clutch firm hold of their prey with the strong claws which terminate the tarsi."Homoptera.We come now to the second group of the order Hemiptera, namely, Homoptera.The insects which compose this division are numerous. They may be arranged into three great families, of the most remarkable members of which we shall give some account. These are theCicadæ, theAphidæor Plant Lice, and theCoccidæ.The Cicada is the type of the first of these families. It has a deafening and monotonous song; as Bilboquet says, in the "Saltimbanques," "those who like that note have enough of it for their money." Virgil pronounced a just criticism on the song of the Cicada: he saw in it nothing better than a hoarse and disagreeable sound:—"At mecum raucis, tua dum vestigia lustro,Sole sub ardenti resonant arbusta cicadis,"says the Latin poet in his "Eclogues," and repeats the same opinion in a verse in his "Georgics:"—"Et cantu querulæ rumpent arbusta cicadæ."The song of the Cicada, so sharp, so discordant, was, however, the delight of the Greeks.Listen to Plato in the first lines of "Phædo:" "By Hera," cries the philosopher-poet, "what a charming place for repose!... It might well be consecrated to some nymphs and to the river Achelöu, to judge by these figures and statues. Taste a little the good air one breathes. How charming, how sweet! One hears as a summer noise an harmonious murmur accompanying the chorus of the Cicada."The Greeks, then, had quite a peculiar taste for the song of the Cicada. They liked to hear its screeching notes, sharp as a point of steel. To enjoy it quite at their ease they shut them up in open wicker-work cages, pretty much in the same way as children shut up the cricket, so as to hear its joyouscri-cri. They carried their love for this insect with the screaming voice so far as to make it the symbol of music. We see, in drawings emblematical of the musical art, a Cicada resting on strings of a cythera. A Grecian legendrelates that one day two cythera players, Eunomos and Aristo, contending on this sonorous instrument, one of the strings of the former's cythera having broken, a Cicada settled on it, and sang so well in place of the broken cord, that Eunomos gained the victory, thanks to this unexpected assistant. Anacreon composed an ode in honour of the Cicada. "Happy Cicada, that on the highest branches of the trees, having drank a little dew, singest like a queen! Thy realm is all thou seest in the fields, all which grows in the forests. Thou art beloved by the labourer; no one harms thee; the mortals respect thee as the sweet harbinger of summer. Thou art cherished by the muses, cherished by Phœbus himself, who has given thee thy harmonious song. Old age does not oppress thee. O good little animal, sprung from the bosom of the earth, loving song, free from suffering, that hast neither blood nor flesh, what is there prevents thee from being a god?"It was in virtue of the false ideas of the Greeks on natural history in general, and on the Cicada in particular, that this little animal symbolised, among the Athenians, nobility of race. They imagined that the Cicada was formed at the expense of the earth, and in its bosom, on which account those who pretended to an ancient and high origin, wore in their hair a golden Cicada. The Locrians had on their coins the image of a Cicada. This is the origin which fable assigns to the custom:—The bank of the river upon which Locris was built was covered with screeching legions of Cicadas; whereas they were never heard (so says the legend) on the opposite bank, on which stood the town Rhegium. In explanation of this circumstance, they pretend that Hercules, wishing one day to sleep on this bank, was so tormented by the "sweet eloquence" of the Cicadas, that, furious at their concert, he asked of the gods that they should never sing there for evermore, and his prayer was immediately granted! This is why the Locrians adopted the Cicada as the arms of their city.The Greeks did not only delight, as poets and musicians, in the song of the Cicada; they were not content with addressing to it poems, with adoring it, and striking medals bearing its image; obedient to their grosser appetites, they ate it. They thus satisfied at the same time both the mind, the spirit, and the body.Fig. 78.—Cicada (Male).Fig. 78.—Cicada (Male).The Cicadas are easily to be recognised by their heavy, very robust, and rather thick-set bodies, by their broad head, unprolonged, having very large and prominentocelli, or simple eyes, three in number, arranged in a triangle on the top of the forehead, and short antennæ. The immature anterior and posterior wings have theshape of a sheath, or case, enveloping the body when the insect is at rest; these are transparent and destitute of colour, or sometimes adorned with bright and varied hues. The legs are not in the least suited for jumping. The female is provided with an auger, with which she makes holes in the bark of trees in which to lay her eggs. The male (Fig. 78) is provided with an organ, not of song, but of stridulation or screeching, which is very rudimentary in the female. We will stop a moment to consider the apparatus for producing the song, or rather the noise, of the male Cicada, and the structure of the female's auger. We are indebted to Réaumur for the discovery of the mechanism by the aid of which the Cicada produces the sharp noise which announces its whereabouts from afar. We will give a summary of the celebrated Memoir in which the French naturalist has so admirably described the musical apparatus of the Cicada.[24]It is not in the throat that the Cicada's organ of sound is placed, but on the abdomen. On examining the abdomen of the male of a large species of Cicada, one remarks on it two horny plates, of pretty good size, which are not found on the females. Each plate has one side straight; the rest of its outline is rounded. It is by the side which is rectilinear that the plate is fixed immediately underneath the third pair of legs. It can be slightly raised, with an effort, by two spine-like processes, each of which presses upon one of the plates, and when it is raised, prevents it from being raised too much, and causes it to fall back again immediately.If the two plates are removed and turned over on the thorax, and the parts which they hide laid bare, one is struck by the appearance which is presented. "One cannot doubt that all one sees has been made to enable the Cicada to sing," says Réaumur. "When one compares the parts which have been arranged so that it may be able to sing, as we may say, from its belly, with the organs of our throat, one finds that ours have not been made with more care than those by means of which the Cicada gives forth sounds which are not always agreeable."We here perceive a cavity in the anterior portion of the abdomen and which is divided into two principal cells by a horny triangle."The bottom of each cell offers to children who catch the Cicada a spectacle which amuses them, and which may be admired by men who know how to make the best use of their reason. The children think they see a little mirror of the thinnest and most transparent glass, or that a little blade of the most beautiful talc is set in the bottom of each of these little cells. That which one might see if this were the case would in no way differ from what one actually sees; the membrane which is stretched out at the bottom of the cells does not yield in transparency either to glass or to talc; and if one looks at it obliquely, one sees in it all the beautiful colours of the rainbow. It seems as if the Cicada has two glazed windows through which one can see into the interior of its body."The horny triangle of which we spoke above only separates in two the lower part of the cavity. The upper part is filled by a white, thin, but strong membrane. This membrane is only drawn tight when the body of the Cicada is raised. But with all this, where is the organ of song? What parts produce the sound? Réaumur will enlighten us on this point.He opened the back of a Cicada, and laid bare the portion of the interior which corresponds with the cavity where the mirrors are, and was immediately struck with the size of the two muscles which meet and are attached to the back of the horny triangle, and to that one of its angles from which start the sides which form the cavities in which are both the mirrors."Muscles of such strength, placed in the belly of the Cicada, and in that part of the belly in which they are found, seem to be only so placed in order that they may move quickly backwards and forwards those parts which, being set in motion, produce the noise or song. And indeed, whilst I was examining one of these muscles, in moving it about gently with a pin, slightly displacing it, and then letting it return to its proper place, it so happened that I made a Cicada that had been dead for many months sing. The song, as might be expected, was not loud; but it was strong enough to lead me on to the discovery of the part to which it was due. I had only to follow the muscle I had been moving, to search for the part on which it abutted."Fig. 79.Musical Apparatus of theMale Cicada.In the large cavity, in which are the mirrors and the other parts mentioned above, there are besides two equal and similar compartments, two cells, in which are placed the instrument of sound. This is a membrane in the shape of a kettledrum, not smooth, but, on the contrary, crumpled and full of wrinkles (Fig. 79). When it is touched it is more sonorous than the driest parchment. If the furrows on itsconvex surface are rubbed with a small body, such as a piece of rolled-up paper, incapable of piercing or tearing it, it is easily made to sound; and the sound is occasioned by the portions of the kettledrum which are depressed by the friction of the small body, returning to their former position as soon as it has ceased to act upon them. It is here that the two strong muscles act whose existence and use were discovered by Réaumur."It is clear," says this naturalist, "that when the muscle is alternately contracted and expanded with rapidity, one convex portion of the kettledrum will be rendered concave, and will then resume its convex form by the force of its own spring. Then this noise will be made, this song of which we have been so long seeking an explanation, because we wished to find out all the parts by means of which He, who never makes anything without its use, willed that it should be produced."Let us add, to complete what we have already said on this subject, that if the kettledrums are the essential organs of the insect's song, the mirrors, the white and wrinkled membranes, and the exterior shutters which cover in the whole apparatus, contribute largely, as Réaumur pointed out, to modify and strengthen the sound.We have said above that the female Cicada does not sing; and so her singing organs are quite rudimentary. This fact, moreover, has been known for ages. Xenarchus, a poet of Rhodes, says, with little gallantry:—"Happy Cicadas! thy females are deprived of voice!"Fig. 80.—Female Cicada laying her eggs in the groove she has bored in the branch of a tree.Nature has indemnified the female Cicada for this privation, by giving her an instrument less noisy indeed, but more useful. This is a sort of auger, destined to penetrate the bark of the branches of trees, and lodged in the last segment of the abdomen, which, for this purpose, is hollowed out groove-wise. By the aid of a system of muscles the auger can be protruded or retracted at pleasure. It is furnished with three implements. In the middle there is a piercer, or bodkin, which when run into a branch supports the insect, and twostylets, whose upper edges, having teeth like a saw, resting back to back, on the middle implement, move up and down it. With this admirable instrument the female Cicada incises obliquely the bark and wood until she has almost reached the pith (Fig. 80). Themale sings while she is at work. When the cell is sufficiently deep and properly prepared, the female lays at the bottom of it from five to eight eggs.From these eggs come very small white grubs (Fig. 81), which leave their nest, descend by the trunk, and bury themselves in the ground, where they devour the roots of the tree. They then become pupæ, and hollowing out the earth with their front legs, which are very much developed, continue to live at the expense of the roots. At the end of spring these pupæ (Fig. 82) come out of the earth, hook themselves on to the trunks of trees, and strip themselves one fine evening of their skin, which remains whole and dried. Very weak at first, these metamorphosed insects drag themselves along with difficulty. But next day, warmed by the first rays of the sun, having had, no doubt, time to reflect on their new social position, and less astonished than they were on the preceding evening, they agitate their wings, they fly, and the males send forth into the air the first notes of their screeching concert. The Cicadas remain on trees, whose sap they suck by means of their sharp-pointed beak. It is difficult enough to catch them, for owing to their large, highly-developed wings, they fly rapidly away on the slightest noise.They inhabit the south of Europe, the whole of Africa from north to south, America in the same latitudes as Europe, the whole of the centre and south of Asia, New Holland, and the islands of Oceania. The Cicada, which in hot climates always exposes itself to the ardour of the most scorching sun, is not found in temperate or cold regions.The consequence is that the southern nations know it very well, whilst in the north the large grasshopper, which is so common in those regions, and whose song closely resembles that of the Cicada, is commonly taken for it. There was to be seen at the Exhibition of Fine Arts in 1866 a picture by M. Aussandon, "La Cigale et la Fourmi," which showed, under an allegorical shape, the subject of La Fontaine's fable. The painter here represented the Cigale, or Cicada, under the form of a magnificent apple-green grasshopper. The artist materialised here, as we may say, the common mistake of the inhabitants of the north, which makes them confound the Cicada with the great green grasshopper.Fig. 81.—Larva of the Cicada.Fig. 82.—Pupa of the Cicada.For the rest, we may, by-the-by, say that La Fontaine's fable of "La Cigale et la Fourmi" is full of errors in natural history. Nothing is easier than to prove the truth of this assertion. From the very first verses, the author shows that he has never observed the animal of which he speaks."La Cigale ayant chantéTout l'été."No Cicada could sing "tout l'été," since it lives at the utmost for a few weeks only."Se trouva fort dépourvueQuand la bise fut venue.""Quand la bise fut venue" means without doubt the month of November or December. But at this season of the year the Cicada has a long time since passed from life to death. When one wanders along the outskirts of woods as early as the month of October, in the south of France, one finds the soil covered with dead Cicadas. La Fontaine'sCigalethen could not have found itself "fort dépourvue," for the simple reason that it was already dead."Elle alla crier famineChez la Fourmi, sa voisine,La priant de lui preterQuelque grain pour subsister."The ant is carnivorous, and although it likes honey, it has nothing to do with grains of wheat, nor with any other grain, of which, according to the fabulist, it had laid up a stock. On the other hand, the Cicada, which he blames for having"Pas un seul petit morceauDe mouche ou de vermisseau,"never dreamt of such victuals, for it lives entirely on the sap of large vegetables. The fables of the poet, who is called in France, one never knows why, "Le bon La Fontaine," teem with errors of the same kind as those we have just pointed out. The habits of animals are nearly always represented as exactly the contrary to what they really are. To initiate himself into the mysteries of the habits of animals, La Fontaine certainly had neither the works of Buffon nor the memoirs of Réaumur, which had not then been written; but had he not the book of Nature?But it is time to mention the principal species of the Cicada. We will describe two: that of the Ash, which lives on those trees in the south of France; and that of the Manna Ash, which is very common in the south-east of France. It is particularly plentiful in the forests of pines which abound between Bayonne and Bordeaux. It is on these two species of Cicada that Réaumur made the beautiful observations of which we gave a summary above.TheCicada plebeiaorTettigonia fraxini, very common in Provence, is found, though rarely, in the forest of Fontainebleau, occasionally in La Brie. It is of a grey yellow below, black above; the head and thorax are marked or striped with black.M. Solier, in a Memoir inserted in the "Annales de la Société Entomologique de France," says that its song, very loud and very piercing, seems to consist of one single note, repeated with rapidity, which insensibly grows weaker after a certain time, and terminates in a kind of whistle, which can be partly imitated by pronouncing the two consonantsst, and which resembles the noise of the air coming out of a little opening in a compressed bladder. When the Cicada sings, it moves its abdomen violently, in such a manner as alternately to move it away from, and to bring it near to, the little covers of the sonorous cavities; to this movement is added a slight trembling of the mesothorax.The same entomologist relates a very interesting observation made on this species of Cicada by his friend, M. Boyer, a chemist at Aix, and which he himself verified. The Cicadas, in general, are very timid, and fly away at the least noise. However, when aCicada is singing, one can approach it, whistling the while in a quavering manner, and imitating as nearly as possible, its cry, but in such a manner as to predominate over it. The insect then descends a small space down the tree, as if to approach the whistler; then it stops. But if one presents a stick to it, continuing to whistle, the Cicada settles on it and begins again to descend backwards. From time to time it stops, as if to listen. At last, attracted, and, as it were, fascinated by the harmony of the whistle, it comes to the observer himself.M. Boyer managed thus to make a Cicada, which continued to sing as long as he whistled in harmony with it, settle on his nose. Charmed by this concert, the insect seemed to have lost its natural timidity.TheCicada orniis of a greenish yellow, spotted with black. The abdomen is encircled by the same colours. The elytra and the wings are hyaline, or glassy, and their veins alternately yellow and brown. The legs are yellow throughout. The song of this species is hoarse, and cannot be heard at any great distance.M. Solier, in the work we quoted just now, says that the song of this Cicada is of a deeper intonation, but that it is quick and is sooner over. It does not terminate in the manner which characterises that of the other species.Next the genusCicadacomesFulgora, whose type is theFulgora lanternaria, or Lantern Fly (Fig. 83).Belonging to South America, these insects are above all remarkable and easy to recognise, by their very large elongated head, which nearly equals three-quarters of the rest of the body. This prolongation is horizontal, vesiculous, enlarged to about the same breadth as the head, and presents above a very great gibbosity. The antennæ are short, with a globular second articulation, and a small terminal hair. The species represented inFig. 83is yellow varied with black. The elytra are of a greenish yellow, sprinkled with black; the wings, of the same colour, have at the extremity a large spot resembling an eye, which is surrounded by a brown circle very broad in front. It inhabits Guyana. This remarkable insect enjoys a great renown with the vulgar, by a peculiarity which might be called its speciality—the property of shining by night or in the dark. Hence its name ofFulgora lanternaria.
III.
HEMIPTERA.
The Hemiptera are particularly distinguished from other kinds of insects by the form of their mouth, which consists of a beak, more or less long, composed of six parts: that is, of a lower lip, or sheath; four internal threads, representing the mandibles and jaws of the grinding insects, and which are the perforating parts of the beaks; and, lastly, of the upper lip or labrum. Owing to this apparatus, these insects are essentially sucking ones, and chiefly nourish themselves with the juices of vegetables, which they draw up with their beak. The wings of the Hemiptera are usually four in number; in some species they are membranous and similar to each other, and in others the upper are of rather harder consistency than the lower ones. In general, the former are quite different from the lower wings, and are only membranous at the tip, whereas the other part is thick, tough, and coriaceous.
The Hemiptera are divided into two very distinct sections. The one is composed of insects whose beak grows from the forehead or upper part of the head, and whose anterior wings are half coriaceous and half membranous, having the base of a different texture from the extremity: these are the Heteroptera (ἑτερος, different; πτερον, wing). The other section is composed of those whose beak grows from the lower part of the head, and whose anterior wings are always of the same consistency throughout: these are the Homoptera (ὁμος, the same; πτερον, wing). We are about to give the history of these two sub-orders.
Heteroptera.
The insects formerly known by the general name of Bugs have been divided by Latreille into two large families, containing: the one theGeocorisæ,[19]or Land Bugs; the other theHydrocorisæ,[20]or Water Bugs.
The land bugs consist of a great number of kinds, which, for the most part, are of little interest. We will only mention here thePeniatomidæ, commonly known as Wood Bugs; theLygæi, Bugs, properly so called; theReduvii, and theHydrometræ.
ThePentatomidæ, which comprise many genera, include the wood bugs of most authors. They are to be found on plants and trees. They fly quickly, but only for a short time.
Fig. 69.—Grey Pentatoma (Raphigaster griseus).Fig. 69.Grey Pentatoma(Raphigaster griseus).
The Ornamented Pentatoma (Strachia[Pentatoma]ornata), known as the Red Cabbage Bug, is very commonly found on the cabbage, and on most of the cruciferous plants. It is variegated with red and black, and its colours are subject to numerous variations. The Grey Pentatoma (Raphigaster griseus),Fig. 69, is common throughout the whole of Europe. In autumn these bugs are frequently to be found on raspberries, to which they impart their disagreeable smell. They are also to be found in quantities on the mullein, when that plant is in flower. The upper parts of the head are of a greyish brown, and are sometimes slightly purple. The coriaceous part of the hemelytra is of a purple tint, but the membranous part is brown. All these parts are covered with black spots, which are only to be seen with a magnifying-glass. The wings are blackish. The under part of the whole body and the feet are of a light and rather yellowish grey, with a considerable number of small black spots. The abdomen is black above; and it is bordered with alternate black and white spots.
We have repeated here the description given of this bug by the illustrious Swedish naturalist, De Geer, because our young readers have most likely met with this insect, or will do so some day when gathering raspberries.
The Grey Pentatoma, marked with black, yellow, and red, is to be found throughout the whole of Europe in cultivated fields and gardens, sometimes also on the trunks of large trees, especially elms. This species, in common with the greater part of those which compose the group we are describing, emits a smell when irritated or menaced by some danger. At other times no odour will be noticed. Let us hear what M. Léon Dufour says on this subject.
"Seize the Pentatoma with a pair of pincers and plunge it into a glass of clear water; look through a magnifying-glass, and you will see innumerable small globules arising from its body, which, bursting on the surface of the water, exhale that odour which is so disagreeable. This vapour, which is essentially acrid, if it happensto touch the eyes, causes a considerable amount of irritation. If one of these insects is held between the fingers, so as not to stop up the odoriferous orifices, and to cause this vapour to touch a part of the skin, a spot, either brown or livid, will ensue on that part, which lotions, though repeatedly applied, will at first fail to remove, and which produces in the cutaneous tissue an alteration similar to that which succeeds the application of mineral acids."
The disagreeable smell exhaled by different species of Pentatoma is the result of a fluid secreted by a single pear-shaped gland, either red or yellow, which occupies the centre of the thorax, and which terminates between the hind legs.
With theSyromastes, which are bugs of this same section, the secretion has, on the contrary, an agreeable smell, which reminds one of that of apples. Many kinds of Pentatoma are destructive to agriculture. Others, however, attack the destructive insects, and ought therefore to be carefully spared. We will mention in this case the Blue Pentatoma, which kills theAltica[21]of the vine.
There may be observed, at the foot and about the lower part of trees, or at the base of walls exposed to the mid-day sun, groups of fifty or sixty small insects pressed close to each other, and often one on the top of the other, their heads in the direction of a centre point. They are red, spotted with black. In the neighbourhood of Paris the children call them "Suisses," probably on account of the red on their bodies, that being the colour of the uniform of the Swiss troops formerly in the service of France. In Burgundy the children call them "petits cochons rouges." They will be found described in Geoffroy's "Histoire des Insectes," under the name of the Red Garden Bug. At the present day they are placed in the genusLygæus.[22]When the bad weather comes, these little "Suisses" take refuge under stones and the bark of trees to pass the winter. During the whole of that season they remain in a sort of torpid state. But in the first days of spring they revive, and resume their ordinary habits. They suck the sap of vegetables, piercing the capsules of divers kinds of mallows, and always keeping in the sunshine.
Fig. 70.—Bed Bug (Acanthia lectularia), magnified.Fig. 70.Bed Bug (Acanthia lectularia),magnified.
Fig. 71.—Egg of Bug, magnified.Fig. 71.Egg of Bug, magnified.
The Bug, popularly so called, or Bed Bug (Acanthia lectularia, orCimex lectularius,Fig. 70), a most disagreeable and stinking insect, abounds in dirty houses, principally in towns, and above all in those of warm countries. It lives in beds, in wood-work, and paper-hangings. There is no crack, however narrow it may be, into which it is unable to slip. It is nocturnal, shunning the light. "Nocturnumfœtidum animal," says Linnæus. Its body is oval, about the fifth of an inch in length, flat, soft, of a brown colour, and covered with little hairs. Its head is provided with two hairy antennæ, and two round black eyes, and has a short beak, curved directly under its thorax, and lying in a shallow groove when the animal is at rest. This beak, composed of three joints, contains four thin, straight, and sharp hairs. The thorax is dilated at the sides. The abdomen is very much developed, orbicular, composed of eight segments, very much depressed, and easily crushed by the fingers. The hemelytra are rudimentary. It has no membranous wings. The tarsi have three articulations, of which the last is provided with two strong hooks.
"These animals," says Moquin-Tandon, in his "Zoologie Médicale," "do not draw up the sanguineous fluid by suction, properly so-called, as leeches do. The organisation of their buccal apparatus does not allow of this. The hairs of the beak applied the one against the other exercise a sort of alternate motion, which draws the blood up into the œsophagus, very much in the same manner as water rises in a chain pump. This rising is assisted by the viscous nature of the fluid, and above all, by the globules it contains." The part of the skin which the Bug has pierced, producing a painful sensation, is easily recognised by a little reddish mark, presenting in its centre a dark spot. Generally a little blister rises on the point pierced, and sometimes, if the Bug-bites are numerous, these blisters become confluent, and resemble a sort of eruption. These disgusting insects lay, towards the month of May, oblong whitish eggs (Fig. 71), having a small aperture, through which the larva comes out. The larva differs from the insect in its perfect state, in its colour, which is pale or yellowish. This insect exists in nearly the whole of Europe, although it is rare or almost unknown in the northern parts. The towns of central Europe are the most infested by this parasite, but those of the north are not completely free from its presence. The Marquis de Custine assures us that at St. Petersburg he found them numerous. It is found also in Scotland; is very rare in the south of Europe; and seldom seen in Italy, where it is, however, replaced by other insects more dangerous or more annoying.
It has been said that the Bug was brought into Europe from America; but Aristotle, Pliny, and Dioscorides mention its existence. It is certain that it was unknown in England till the beginning of the sixteenth century. A celebrated traveller, a Spanish naturalist, Azara, has remarked that the Bug does not infest man in his savage state, but only when congregated together in a state of civilisation, and in houses, as in Europe. From this he concluded that the Bug was not created till long after man, when, after many centuries had elapsed since his appearance on the globe, men formed themselves into societies, into republics, or little states.
The bug is not a gluttonous insect, always bloodthirsty; on the contrary, its sobriety is remarkable. It is only after a prolonged fast that it bites animals; and Audouin has stated that it can live a year and even two years without food.
From time immemorial a number of different means have been employed for destroying these insects; but in spite of all, nothing is more difficult than to get rid of them from wood-work and paper-hangings, when they have once infested them. In general, strong odours cause their death. And so, to rid oneself of these disagreeable guests, it has been recommended to use tobacco smoke, essence of turpentine, the fumes of sulphur, &c. Mercurial ointment and corrosive sublimate are also excellent means for their destruction; and for the same purpose the merits of a plant belonging to the order Cruciferæ,Lepidium ruderale, have been much vaunted; and more recently still, the root of the Pyrethrum, a species of camomile, reduced to powder, and blown into the furniture or wood-work. This powder is known and employed at Paris under the name of "poudre insecticide."
There are two other kinds of bugs (Acanthia) which attack men. The one is theAcanthia ciliata, which has been found in the houses of Kazan, and which differs from the bed bug not only in its form, but also in its habits. It does not live in companies, in the narrow cracks of furniture, but moves about alone, at a slow pace, over walls or the counterpanes of beds. Its beak is very long, and its bite is very painful, and produces obstinate swellings.
The other species is theAcanthia rotundata, which is found in the Island of La Réunion, and attacks men in the same way as does the European bug. Two species of the same genus live as parasites on swallows and domestic pigeons. There is another species, which is peculiar to the bats of our climates.
TheReduvius personatus, called also Fly Bug, by Geoffroy, the old historian of the insects of the environs of Paris, is commonenough in France. It keeps to the houses, and is found especially near ovens and chimney-pieces. It is about three-quarters of an inch in length, oblong, flat on its upper side, brownish, has horizontal hemelytra crossed over each other, and very fully developed wings, which serve for flight. Its head, narrow, supported by a well-defined neck, is provided with two composite and two simple eyes. It requires, no doubt, to see very clearly, as it flies by night. It should not be caught without great caution. If you desire to examine it closely, when, in the hottest part of the summer, it comes in the evening and flutters round the lights, you must be careful how you seize it, for it wounds. The wounds inflicted by it are very painful—more painful than those of the bee—and they immediately cause a numbness.
As theReduviuskills different insects very rapidly, by piercing them with its long beak, it is probable that it secretes some kind of venom. But as yet the organ that produces this poison has not been discovered. However that may be, its beak is curved, and about the tenth of an inch long, the surface bristling with hairs. It is composed of three joints, and contains four stiff, lanceolate, and very pointed squamose hairs.
This insect often seeks its prey in places where spiders spin their webs. When they walk on, or are caught in, the spiders' webs, the spiders take care not to seize them, for they fear their beak. They prudently allow them to struggle about the nets, where they very soon die of hunger. TheReduviusis often seen, either a prisoner or dead, in the midst of a spider's web.
"This bug," says Charles de Geer, "has, in the pupal condition, or before its wings are developed, an appearance altogether hideous and revolting. One would take it, at the first glance, for one of the ugliest of spiders. That which above all renders it so disagreeable to the sight is that it is entirely covered, and, as it were, enveloped with a greyish matter, which is nothing else but the dust which one sees in the corners of badly-swept rooms, and which is generally mixed with sand and particles of wool, or silk, or other similar matters which come from furniture and clothes, rendering the legs of this insect thick and deformed, and giving to its whole body a very singular appearance."
What instincts! what habits! Under this borrowed costume, under this cloak, which is no part of itself, the insect, as it were, masked, has become twice its real size. What becomes of its disguise, and how does it manage to walk? Of what use to it is this dirty and grotesque fancy dress?
Let us listen to De Geer. "It walks as fast, when it likes, as other bugs; but generally its walk is slow, and it moves with measured steps. After having taken one step forward, it stops a while, and then takes another, leaving, at each movement, the opposite leg in repose; it goes on thus continually, step after step in succession, which gives it the appearance of walking as if by jerks, and in measure. It makes almost the same sort of movement with its antennæ, which it moves also at intervals and by jerks. All these movements have a more singular appearance than it is possible for us to describe."[23]
By means of this disguise, it can approach little animals, which become its prey, such as flies, spiders, bed bugs.
To see what a curious appearance theReduviuspresents, one should take off its borrowed costume. Then you will observe an entirely different animal, and one which has nothing repulsive about it. With the exception of the hemelytra and wings, which it has not yet got, all its parts have the form which they are to have later, after the wings are developed.
Fig. 72 represents, from Charles de Geer's Memoir, the pupa of theReduvius personatuscovered with dust, and resembling a spider;Fig. 73the same insect cleaned, freed from the cloak of dust which served to disguise it.
Fig. 74.—Hydrometra stagnorum.
TheHydrometræ(from ὑδωρ, water, and μετρειν, to measure)have linear bodies. The head, which forms nearly the third of the entire length, is furnished with two long antennæ, and armed with a thin, hair-like beak. The legs are long, and of equal length. The reader may have often seen theHydrometra stagnorumwalking by jerks on the surface of the water (Fig. 74). The body and legs are of a ferruginous colour, the hemelytra a dull brown, and the wings hyaline, or glassy, and slightly blackish. Geoffroy says that it resembles a long needle, and calls it the Needle Bug.
TheHydrocorisæ, or Water Bugs, have the antennæ shorter than the head, or scarcely attaining to its length, and inserted and hidden under the eyes, which are in general of remarkable size. All these Hemiptera are aquatic and carnivorous. We will mention the two principal types, theNepæ, or Water Scorpions, and theNotonectæ, or Boatmen.
Fig. 75.—Nepa cinerea.
TheNepa cinerea(Fig. 75), which Geoffroy calls the Oval-bodied Water Scorpion, and which he also designates by the name of the Water Spider, is very common in the stagnant waters of ponds and ditches. Its body, oval, very flat, of an ashy colour, with red on the abdomen, is four-fifths of an inch long. The hemelytra are horizontal, coriaceous, and of a dirty grey colour. Its front legs, with short haunches, and very broad thighs, are terminated by strong pincers, which give to the insect a strong resemblance to the scorpion. It is by folding back the leg and the tarsus under the thigh, that the animal holds its prey, and sucks it with its rostrum or beak.
This rostrum is composed of three joints, and contains four pointed bristles. Two present on one side a sort of narrow sharp blade, and have teeth towards their base. Of the two others, the one is a thin smooth needle, the other is provided with hairs directed backwards and forwards.
It is with this rostrum, which resembles a case of surgical instruments, that theNepapierces and sucks little aquatic insects, not even sparing its own species. Its wound is painful to man, but not in the least dangerous. With its four hind legs theNepaswims, but at a very slow pace. It generally drags itself along the bottom of thewater, on the mud, and does not avoid the hand put out to seize it. Its body is terminated by a tail, composed of two grooved threads, which, when applied together, form a tube, capable of being moved from side to side. Through this canal it breathes the outer air; it puts the end of it out of the water, and the air enters it by inspiration. Some very small hairs, with which the interiors of the grooves are lined, interlace each other, and prevent the water from penetrating into the canal. It is probable that this same canal serves also for depositing the eggs. These last resemble small seeds, covered with points, and are buried in the stalks of aquatic plants.
Next to theNepacomes theRanatra, with a cylindrical, elongated, linear body, with very long and very thin hind legs, and of which one species, which Geoffroy calls the "aquatic scorpion with an elongated body," is common everywhere in stagnant waters in spring. It is brownish, carnivorous, and very voracious.
Fig. 76.—Corixa striata.
We must now mention the genusCorixa, of which one species, theCorixa striata, is very common. This insect walks badly and slowly on land, but swims and cuts through the water with a prodigious rapidity.
However, it is not to delay over this last species that we have here mentioned the name of this genus. Some insects which belong to it, and which are found in Mexico, deserve to be alluded to, on account of certain peculiarities which their eggs present. A naturalist, M. Virlet d'Aoust, has published the following details on this subject:—
"Thousands of small amphibious flies," he says, "flit about in the air on the surface of lakes, and diving down into the water many feet, and even many fathoms, go to the bottom to lay their eggs, and only emerge from the water probably to die close by. We were fortunate enough to be present at a great fishing or harvest of the eggs, which, under the Mexican name ofhautle(haoutle), serve for food to the Indians, who seem to be no less fond of them than the Chinese are of their swallows' nests, which they resemble somewhat in taste; only thehautleis far from commanding such high prices as the Chinese pay for their birds' nests, which for that reason are reserved entirely for the tables of the rich; while, for a few smallcoins, we were able to carry away with us about a bushel of thehautle, a portion of which, at our request, Mme. B—— was kind enough to prepare for us.
"They dress these in different ways, but generally make a sort of cake, which is served up with a sauce, to which the Mexicans give a zest, as they do indeed to all their dishes, by adding to itchilié, which is composed of green pimento crushed. This is how the natives proceed when they are fishing forhautle: they form with reeds bent together a sort of fasces, which they place vertically in the lake at some distance from the bank, and as these are bound together by one of the reeds, the ends of which are so arranged as to form an indicating buoy, it is easy to draw them out at will. Twelve to fifteen days suffice for each reed in these fasces to be entirely covered with eggs, which they thus fish up by millions. The former are then left to dry in the sun, on a cloth, for an hour or more; the grains are then easily detached. After this operation, they are replaced in the water for the next hautle harvest."
M. Virlet had attributed to flies the eggs of which we have been speaking. But in 1851 M. Guérin-Méneville having received, transmitted to him by M. Ghiliani, eggs of whichhautleis made, and some of the insects said to produce them, stated that the latter belonged to two different species. The one had been known a long time since under the name ofCorixa mercenaria; M. Guérin-Méneville called the otherCorixa femorata.
The same entomologist discovered, among the eggs of these two species, other eggs of a more considerable size, and which he attributed to a new species of the genusNotonecta, about which we are now going to say a few words.
TheNotonecta glauca, which Geoffroy calls the Large Bug with Oars ("Grande punaise à avirons"), is very common in ditches, reservoirs, and stagnant waters. Its body is oblong, narrow, contracted posteriorly, convex above, flat below, having, at its sides and its extremities, hairs which, when spread out, support the animal on the water. Its head is large and of a slightly greenish grey, and has on each of its sides a very large eye of a pale brown colour. Its thorax is greyish, the hemelytra of a greenish grey, the membranous wings white. Of its legs, the front four are short; but the hind legs, almost twice as long, are furnished with long hairs, and resemble oars. It is with the aid of these that the animal moves through the water; and it does so in a singular manner, placing itself on its back, and generally in an inclined position, as inFig. 77.
When this insect, on the contrary, drags itself along on the mud,the front legs are those which it employs, the hind legs being idle, and merely drawn along behind it. It is generally towards the evening or during the night that it comes out of the water, to walk and to fly, if it wishes to pass from one marsh to another.
Fig. 77.—Notonecta glauca.
This bloodthirsty insect lives entirely by rapine; it is one of the most carnivorous of insects. Those which it attacks die very soon after they have been hurt by it. De Geer thinks that the water bug drops into the wound a poisonous humour. It seizes upon insects much bigger, and apparently much stronger, than itself, and does not spare its own species.
The instrument with which theNotonectaattacks its prey is composed of a very strong and very long conical beak, formed of four joints. The sucker is composed of an upper piece, short and pointed, and of four fine pointed hairs.
The female of theNotonecta glaucalays a great number of eggs, white, and of elongated shape, which it deposits on the stems and leaves of aquatic plants. The eggs are hatched at the beginning of spring, or in May, and the young ones at once begin to swim about like their mother, on their backs, belly upwards. M. Léon Dufour says on this subject:—
"A dorsal region, raised like a donkey's back, or like the rounded keel of a boat, and covered with a velvety substance, which renders it impermeable, numerous fine fringes which garnish either the hind legs, or the borders of the abdomen and thorax, or lastly in a double row form a crest or comb running down the surface of the belly, and which spread themselves out or fold themselves in at the will of the insect, just like fins, favour both this supine attitude and the accuracy of the swimming movements of theNotonectæ. Since Nature—which seems often to delight in producing extraordinary exceptions to her ordinary rules, thus bearing witness to the immensity of her resources—had condemned this animal to pass its life in an inverted position, it was necessary, for the maintenance of its existence, that it should provide it with an organisation in harmony with this attitude. It is also for this object that its head is bent over its chest; that its eyes, of an oval shape, can see below from above; that the front as well as the middle legs, agile and curved, solely destined for prehension, canto a certain extent become unbent by means of the elongated haunches which fix them to the body, and clutch firm hold of their prey with the strong claws which terminate the tarsi."
Homoptera.
We come now to the second group of the order Hemiptera, namely, Homoptera.
The insects which compose this division are numerous. They may be arranged into three great families, of the most remarkable members of which we shall give some account. These are theCicadæ, theAphidæor Plant Lice, and theCoccidæ.
The Cicada is the type of the first of these families. It has a deafening and monotonous song; as Bilboquet says, in the "Saltimbanques," "those who like that note have enough of it for their money." Virgil pronounced a just criticism on the song of the Cicada: he saw in it nothing better than a hoarse and disagreeable sound:—
"At mecum raucis, tua dum vestigia lustro,Sole sub ardenti resonant arbusta cicadis,"
says the Latin poet in his "Eclogues," and repeats the same opinion in a verse in his "Georgics:"—
"Et cantu querulæ rumpent arbusta cicadæ."
The song of the Cicada, so sharp, so discordant, was, however, the delight of the Greeks.
Listen to Plato in the first lines of "Phædo:" "By Hera," cries the philosopher-poet, "what a charming place for repose!... It might well be consecrated to some nymphs and to the river Achelöu, to judge by these figures and statues. Taste a little the good air one breathes. How charming, how sweet! One hears as a summer noise an harmonious murmur accompanying the chorus of the Cicada."
The Greeks, then, had quite a peculiar taste for the song of the Cicada. They liked to hear its screeching notes, sharp as a point of steel. To enjoy it quite at their ease they shut them up in open wicker-work cages, pretty much in the same way as children shut up the cricket, so as to hear its joyouscri-cri. They carried their love for this insect with the screaming voice so far as to make it the symbol of music. We see, in drawings emblematical of the musical art, a Cicada resting on strings of a cythera. A Grecian legendrelates that one day two cythera players, Eunomos and Aristo, contending on this sonorous instrument, one of the strings of the former's cythera having broken, a Cicada settled on it, and sang so well in place of the broken cord, that Eunomos gained the victory, thanks to this unexpected assistant. Anacreon composed an ode in honour of the Cicada. "Happy Cicada, that on the highest branches of the trees, having drank a little dew, singest like a queen! Thy realm is all thou seest in the fields, all which grows in the forests. Thou art beloved by the labourer; no one harms thee; the mortals respect thee as the sweet harbinger of summer. Thou art cherished by the muses, cherished by Phœbus himself, who has given thee thy harmonious song. Old age does not oppress thee. O good little animal, sprung from the bosom of the earth, loving song, free from suffering, that hast neither blood nor flesh, what is there prevents thee from being a god?"
It was in virtue of the false ideas of the Greeks on natural history in general, and on the Cicada in particular, that this little animal symbolised, among the Athenians, nobility of race. They imagined that the Cicada was formed at the expense of the earth, and in its bosom, on which account those who pretended to an ancient and high origin, wore in their hair a golden Cicada. The Locrians had on their coins the image of a Cicada. This is the origin which fable assigns to the custom:—
The bank of the river upon which Locris was built was covered with screeching legions of Cicadas; whereas they were never heard (so says the legend) on the opposite bank, on which stood the town Rhegium. In explanation of this circumstance, they pretend that Hercules, wishing one day to sleep on this bank, was so tormented by the "sweet eloquence" of the Cicadas, that, furious at their concert, he asked of the gods that they should never sing there for evermore, and his prayer was immediately granted! This is why the Locrians adopted the Cicada as the arms of their city.
The Greeks did not only delight, as poets and musicians, in the song of the Cicada; they were not content with addressing to it poems, with adoring it, and striking medals bearing its image; obedient to their grosser appetites, they ate it. They thus satisfied at the same time both the mind, the spirit, and the body.
Fig. 78.—Cicada (Male).Fig. 78.—Cicada (Male).
The Cicadas are easily to be recognised by their heavy, very robust, and rather thick-set bodies, by their broad head, unprolonged, having very large and prominentocelli, or simple eyes, three in number, arranged in a triangle on the top of the forehead, and short antennæ. The immature anterior and posterior wings have theshape of a sheath, or case, enveloping the body when the insect is at rest; these are transparent and destitute of colour, or sometimes adorned with bright and varied hues. The legs are not in the least suited for jumping. The female is provided with an auger, with which she makes holes in the bark of trees in which to lay her eggs. The male (Fig. 78) is provided with an organ, not of song, but of stridulation or screeching, which is very rudimentary in the female. We will stop a moment to consider the apparatus for producing the song, or rather the noise, of the male Cicada, and the structure of the female's auger. We are indebted to Réaumur for the discovery of the mechanism by the aid of which the Cicada produces the sharp noise which announces its whereabouts from afar. We will give a summary of the celebrated Memoir in which the French naturalist has so admirably described the musical apparatus of the Cicada.[24]
It is not in the throat that the Cicada's organ of sound is placed, but on the abdomen. On examining the abdomen of the male of a large species of Cicada, one remarks on it two horny plates, of pretty good size, which are not found on the females. Each plate has one side straight; the rest of its outline is rounded. It is by the side which is rectilinear that the plate is fixed immediately underneath the third pair of legs. It can be slightly raised, with an effort, by two spine-like processes, each of which presses upon one of the plates, and when it is raised, prevents it from being raised too much, and causes it to fall back again immediately.
If the two plates are removed and turned over on the thorax, and the parts which they hide laid bare, one is struck by the appearance which is presented. "One cannot doubt that all one sees has been made to enable the Cicada to sing," says Réaumur. "When one compares the parts which have been arranged so that it may be able to sing, as we may say, from its belly, with the organs of our throat, one finds that ours have not been made with more care than those by means of which the Cicada gives forth sounds which are not always agreeable."
We here perceive a cavity in the anterior portion of the abdomen and which is divided into two principal cells by a horny triangle.
"The bottom of each cell offers to children who catch the Cicada a spectacle which amuses them, and which may be admired by men who know how to make the best use of their reason. The children think they see a little mirror of the thinnest and most transparent glass, or that a little blade of the most beautiful talc is set in the bottom of each of these little cells. That which one might see if this were the case would in no way differ from what one actually sees; the membrane which is stretched out at the bottom of the cells does not yield in transparency either to glass or to talc; and if one looks at it obliquely, one sees in it all the beautiful colours of the rainbow. It seems as if the Cicada has two glazed windows through which one can see into the interior of its body."
The horny triangle of which we spoke above only separates in two the lower part of the cavity. The upper part is filled by a white, thin, but strong membrane. This membrane is only drawn tight when the body of the Cicada is raised. But with all this, where is the organ of song? What parts produce the sound? Réaumur will enlighten us on this point.
He opened the back of a Cicada, and laid bare the portion of the interior which corresponds with the cavity where the mirrors are, and was immediately struck with the size of the two muscles which meet and are attached to the back of the horny triangle, and to that one of its angles from which start the sides which form the cavities in which are both the mirrors.
"Muscles of such strength, placed in the belly of the Cicada, and in that part of the belly in which they are found, seem to be only so placed in order that they may move quickly backwards and forwards those parts which, being set in motion, produce the noise or song. And indeed, whilst I was examining one of these muscles, in moving it about gently with a pin, slightly displacing it, and then letting it return to its proper place, it so happened that I made a Cicada that had been dead for many months sing. The song, as might be expected, was not loud; but it was strong enough to lead me on to the discovery of the part to which it was due. I had only to follow the muscle I had been moving, to search for the part on which it abutted."
Fig. 79.Musical Apparatus of theMale Cicada.
In the large cavity, in which are the mirrors and the other parts mentioned above, there are besides two equal and similar compartments, two cells, in which are placed the instrument of sound. This is a membrane in the shape of a kettledrum, not smooth, but, on the contrary, crumpled and full of wrinkles (Fig. 79). When it is touched it is more sonorous than the driest parchment. If the furrows on itsconvex surface are rubbed with a small body, such as a piece of rolled-up paper, incapable of piercing or tearing it, it is easily made to sound; and the sound is occasioned by the portions of the kettledrum which are depressed by the friction of the small body, returning to their former position as soon as it has ceased to act upon them. It is here that the two strong muscles act whose existence and use were discovered by Réaumur.
"It is clear," says this naturalist, "that when the muscle is alternately contracted and expanded with rapidity, one convex portion of the kettledrum will be rendered concave, and will then resume its convex form by the force of its own spring. Then this noise will be made, this song of which we have been so long seeking an explanation, because we wished to find out all the parts by means of which He, who never makes anything without its use, willed that it should be produced."
Let us add, to complete what we have already said on this subject, that if the kettledrums are the essential organs of the insect's song, the mirrors, the white and wrinkled membranes, and the exterior shutters which cover in the whole apparatus, contribute largely, as Réaumur pointed out, to modify and strengthen the sound.
We have said above that the female Cicada does not sing; and so her singing organs are quite rudimentary. This fact, moreover, has been known for ages. Xenarchus, a poet of Rhodes, says, with little gallantry:—
"Happy Cicadas! thy females are deprived of voice!"
Fig. 80.—Female Cicada laying her eggs in the groove she has bored in the branch of a tree.
Nature has indemnified the female Cicada for this privation, by giving her an instrument less noisy indeed, but more useful. This is a sort of auger, destined to penetrate the bark of the branches of trees, and lodged in the last segment of the abdomen, which, for this purpose, is hollowed out groove-wise. By the aid of a system of muscles the auger can be protruded or retracted at pleasure. It is furnished with three implements. In the middle there is a piercer, or bodkin, which when run into a branch supports the insect, and twostylets, whose upper edges, having teeth like a saw, resting back to back, on the middle implement, move up and down it. With this admirable instrument the female Cicada incises obliquely the bark and wood until she has almost reached the pith (Fig. 80). Themale sings while she is at work. When the cell is sufficiently deep and properly prepared, the female lays at the bottom of it from five to eight eggs.
From these eggs come very small white grubs (Fig. 81), which leave their nest, descend by the trunk, and bury themselves in the ground, where they devour the roots of the tree. They then become pupæ, and hollowing out the earth with their front legs, which are very much developed, continue to live at the expense of the roots. At the end of spring these pupæ (Fig. 82) come out of the earth, hook themselves on to the trunks of trees, and strip themselves one fine evening of their skin, which remains whole and dried. Very weak at first, these metamorphosed insects drag themselves along with difficulty. But next day, warmed by the first rays of the sun, having had, no doubt, time to reflect on their new social position, and less astonished than they were on the preceding evening, they agitate their wings, they fly, and the males send forth into the air the first notes of their screeching concert. The Cicadas remain on trees, whose sap they suck by means of their sharp-pointed beak. It is difficult enough to catch them, for owing to their large, highly-developed wings, they fly rapidly away on the slightest noise.
They inhabit the south of Europe, the whole of Africa from north to south, America in the same latitudes as Europe, the whole of the centre and south of Asia, New Holland, and the islands of Oceania. The Cicada, which in hot climates always exposes itself to the ardour of the most scorching sun, is not found in temperate or cold regions.The consequence is that the southern nations know it very well, whilst in the north the large grasshopper, which is so common in those regions, and whose song closely resembles that of the Cicada, is commonly taken for it. There was to be seen at the Exhibition of Fine Arts in 1866 a picture by M. Aussandon, "La Cigale et la Fourmi," which showed, under an allegorical shape, the subject of La Fontaine's fable. The painter here represented the Cigale, or Cicada, under the form of a magnificent apple-green grasshopper. The artist materialised here, as we may say, the common mistake of the inhabitants of the north, which makes them confound the Cicada with the great green grasshopper.
For the rest, we may, by-the-by, say that La Fontaine's fable of "La Cigale et la Fourmi" is full of errors in natural history. Nothing is easier than to prove the truth of this assertion. From the very first verses, the author shows that he has never observed the animal of which he speaks.
"La Cigale ayant chantéTout l'été."
No Cicada could sing "tout l'été," since it lives at the utmost for a few weeks only.
"Se trouva fort dépourvueQuand la bise fut venue."
"Quand la bise fut venue" means without doubt the month of November or December. But at this season of the year the Cicada has a long time since passed from life to death. When one wanders along the outskirts of woods as early as the month of October, in the south of France, one finds the soil covered with dead Cicadas. La Fontaine'sCigalethen could not have found itself "fort dépourvue," for the simple reason that it was already dead.
"Elle alla crier famineChez la Fourmi, sa voisine,La priant de lui preterQuelque grain pour subsister."
The ant is carnivorous, and although it likes honey, it has nothing to do with grains of wheat, nor with any other grain, of which, according to the fabulist, it had laid up a stock. On the other hand, the Cicada, which he blames for having
"Pas un seul petit morceauDe mouche ou de vermisseau,"
never dreamt of such victuals, for it lives entirely on the sap of large vegetables. The fables of the poet, who is called in France, one never knows why, "Le bon La Fontaine," teem with errors of the same kind as those we have just pointed out. The habits of animals are nearly always represented as exactly the contrary to what they really are. To initiate himself into the mysteries of the habits of animals, La Fontaine certainly had neither the works of Buffon nor the memoirs of Réaumur, which had not then been written; but had he not the book of Nature?
But it is time to mention the principal species of the Cicada. We will describe two: that of the Ash, which lives on those trees in the south of France; and that of the Manna Ash, which is very common in the south-east of France. It is particularly plentiful in the forests of pines which abound between Bayonne and Bordeaux. It is on these two species of Cicada that Réaumur made the beautiful observations of which we gave a summary above.
TheCicada plebeiaorTettigonia fraxini, very common in Provence, is found, though rarely, in the forest of Fontainebleau, occasionally in La Brie. It is of a grey yellow below, black above; the head and thorax are marked or striped with black.
M. Solier, in a Memoir inserted in the "Annales de la Société Entomologique de France," says that its song, very loud and very piercing, seems to consist of one single note, repeated with rapidity, which insensibly grows weaker after a certain time, and terminates in a kind of whistle, which can be partly imitated by pronouncing the two consonantsst, and which resembles the noise of the air coming out of a little opening in a compressed bladder. When the Cicada sings, it moves its abdomen violently, in such a manner as alternately to move it away from, and to bring it near to, the little covers of the sonorous cavities; to this movement is added a slight trembling of the mesothorax.
The same entomologist relates a very interesting observation made on this species of Cicada by his friend, M. Boyer, a chemist at Aix, and which he himself verified. The Cicadas, in general, are very timid, and fly away at the least noise. However, when aCicada is singing, one can approach it, whistling the while in a quavering manner, and imitating as nearly as possible, its cry, but in such a manner as to predominate over it. The insect then descends a small space down the tree, as if to approach the whistler; then it stops. But if one presents a stick to it, continuing to whistle, the Cicada settles on it and begins again to descend backwards. From time to time it stops, as if to listen. At last, attracted, and, as it were, fascinated by the harmony of the whistle, it comes to the observer himself.
M. Boyer managed thus to make a Cicada, which continued to sing as long as he whistled in harmony with it, settle on his nose. Charmed by this concert, the insect seemed to have lost its natural timidity.
TheCicada orniis of a greenish yellow, spotted with black. The abdomen is encircled by the same colours. The elytra and the wings are hyaline, or glassy, and their veins alternately yellow and brown. The legs are yellow throughout. The song of this species is hoarse, and cannot be heard at any great distance.
M. Solier, in the work we quoted just now, says that the song of this Cicada is of a deeper intonation, but that it is quick and is sooner over. It does not terminate in the manner which characterises that of the other species.
Next the genusCicadacomesFulgora, whose type is theFulgora lanternaria, or Lantern Fly (Fig. 83).
Belonging to South America, these insects are above all remarkable and easy to recognise, by their very large elongated head, which nearly equals three-quarters of the rest of the body. This prolongation is horizontal, vesiculous, enlarged to about the same breadth as the head, and presents above a very great gibbosity. The antennæ are short, with a globular second articulation, and a small terminal hair. The species represented inFig. 83is yellow varied with black. The elytra are of a greenish yellow, sprinkled with black; the wings, of the same colour, have at the extremity a large spot resembling an eye, which is surrounded by a brown circle very broad in front. It inhabits Guyana. This remarkable insect enjoys a great renown with the vulgar, by a peculiarity which might be called its speciality—the property of shining by night or in the dark. Hence its name ofFulgora lanternaria.