Fig. 231.—Attacus (Bombyx) Atlas.Fig. 231.—Attacus (Bombyx) Atlas.Fig. 232.—The Lackey (Bombyx neustria).One part ofFig. 233shows the arrangement of the caterpillars on coming out of the nest. These caterpillars are furnished with long hairs, slightly tufted, which come off with the greatest ease, and which if they penetrate into the skin, cause violent itching. In 1865 a number of the alleys of the Bois de Boulogne were shut up from the public in order to save them from this annoyance. These caterpillars construct a covering common to them all, in which they live, and transform themselves therein, each insect making for his own private use a small cocoon. This insect is said to have been found in England, but there is not sufficient evidence to admit it into our lists.Fig. 233.—Larvæ of the Procession MothFig. 233.—Larvæ of the Procession Moth (Bombyx processionea).Fig. 234.—The Vapourer Moth (Orgyia antiqua), male and female.TheOrgyiascomprise a great number of small species, of a dark colour, which do a great deal of damage to our forest trees. In September and October the male of theOrgyia antiqua, with his tawny wings, may often be seen flying about the streets of London. The female (Fig. 234) is remarkable, as she has only the rudiments of wings, and only goes as far as the side of her cocoon. The caterpillar of theOrgyia pudibunda, called also the Hop Dog, attacks almost every sort of tree. When the state of the atmosphere favours their propagation, they appear in fearful quantities, and cause the greatest havoc. During the autumn of 1828, in the environs of Phalsbourg, they were to be counted by millions. The extent of the woods laid waste was calculated at about fifteen hundred hectares. It is common in this country.Fig. 235.—Orgyia pudibunda.Among the genusLiparis, the species of which are also very destructive to trees, we must mention the Brown-tailed Moth (Liparis chrysorrhœa,Fig. 236), a species by no means rare in England. Thecaterpillars live in quantities, on apple, pear, and elm trees, and destroy the plantations of the promenades of Paris.Fig. 236.—Liparis chrysorrhœa.The females of this genus tear off the fur from the extremity of their abdomens to make a soft bed for their eggs, and to preserve them from the cold. And yet they are never to see their young, for they die after they have laid their eggs. Another tribe ofBombycinacontains species of a small size, which are remarkable from the habits of their caterpillars, which make, with foreign bodies, cases, in the interior of which they live and undergo their metamorphoses.The caterpillars of the genusPsychelive in a case composed of fragments of leaves, of bits of grass and straw, of small sticks of wood, or of little stones, stuck together, and intermixed with silky threads.Fig. 237.—Case of Psyche muscella.Fig. 238.—Psyche muscella.Fig. 239.—Case of Pysche rubicolella.Fig. 240.—Case of Psyche graminella.Fig. 241.—Larva of Psyche graminella.Fig. 242.—Psyche graminella.VII.—The Goat-moth (Cossus ligniperda). Larva, pupa, and perfect insect.1, 2. Perfect insect. 3. Pupa. 4. Larva.We give a representation (in Figs.237,239, and240) of the cases of the caterpillars of three different kinds. The females of these moths are completely destitute of wings, and resemble caterpillars. As a general rule they hardly ever leave their case. The males (Figs.238,242) are of a blackish grey, and fly very swiftly.The caterpillars of the genusHepialusare difficult to observe, as they live in the interior of the roots of various vegetables. Such is the common Ghost Moth (Hepialus humuli), which sometimes causes the greatest damage.Fig. 243.—Zeuzera æsculi.Fig. 243.—Zeuzera æsculi.The type of the genusZeuzeraisZeuzera æsculi, or Wood Leopard (Fig. 243). It has white wings with large blackish blue spots on the anterior, and small black spots on the posterior wings. The caterpillar, of a vivid yellow, spotted with black, lives in the interior of the trunks of a great many trees, principally the chestnut, the elm, the lime, and the pear tree. This moth, which is known also by the name of Coquette, is to be seen in the evening flying about the public gardens of Paris, and is not rare in England. The most celebrated species of the allied genusCossusis the Wood-boring Goat Moth (Cossus ligniperda), figured in theopposite plate. The moth has a heavy brownish body and greyish wings streaked with black. It is found in most parts of Europe. The caterpillar is of a reddish colour, as if it had on a leathern jerkin, and disgorges a liquid which is believed to soften ligneous fibres, and it lives in the interiorof willows and other trees. It was on this caterpillar that Lyonnet made his admirable anatomical researches.Fig. 244.—Larva of Dicranura vinula.Fig. 245.—Dicranura vinula.Another tribe ofBombycinacomprises some very strange caterpillars, whose hindermost feet are changed into forked prolongations, which they move about in a threatening manner. These sort of fly-traps are perhaps meant to keep at a distance those insects which would lay their eggs upon the caterpillar's body. The caterpillarsofDicranuraare of this kind. We give a representation of the caterpillar and the moth of the Puss Moth (Dicranura vinula, Figs.244,245), as also the moth of theDicranura verbasci, the former of which is common in England, and the larva may be found during the late summer and early autumn feeding on poplars and willows; and of the caterpillar ofStauropus fagi, the Lobster Moth (Fig. 247), rare in France, whose appearance is strange indeed. The moths, on the contrary, have nothing about them remarkable.Fig. 246.—Dicranura verbasci.Fig. 247.—Larva of the Lobster Moth (Stauropus fagi).TheNoctuinaare a group of Lepidoptera of middling size, and generally found in woods, meadows, and gardens, where their caterpillars have lived. They seldom fly till about sunset, or during the night. Their upper wings are of a dark colour, with spots in the middle of a particular shape. Their lower wings are of various colours, often whitish, sometimes red or yellow.Fig. 248.—Noctua tegamon.Fig. 249.—Noctua nebulosa.We give representations of some of the species of this group.[69]Noctua tegamon,Fig. 248;Noctua nebulosa,Fig. 249;Noctua musiva,Fig. 250;Noctua brunnea,Fig. 251;Catocala fraxini,Fig. 252;Catocala Americana,Fig. 253;Catocala paranympha,Fig. 254;Catocala nupta,Fig. 255, the Red Underwing; andErebus strix,Fig. 256.Fig. 250.—Noctua musiva.Fig. 251.—Noctua brunnea.The bodies of these moths are robust and sometimes massive, and are scaly rather than woolly. The thorax is sometimes bristling with hairy tufts.This genus includes 800 species, of which there are about 300 in France. The caterpillars of theNoctuinaare smooth orvery slightly covered with hair, usually of a pale colour, and live on low plants, of which they devour, some the leaves, others the roots; then it is they are most destructive to agriculture. There are some of them which eat any caterpillars they may chance to meet, and even those of their own species, leaving nothing but the skin. Some of them surround themselves with a light cocoon before becoming chrysalides; others bury themselves in soft, well-pulverised soil.Fig. 252.—Catocala fraxini.Fig. 253.—Catocala Americana.Fig. 254.—Catocala paranympha.Fig. 255.—Catocala nupta.Fig. 256.—Erebus strix.The family ofGeometrinæ, or Geometers, comprises moths of a middling size, and usually flying after sunset and during the night.[70]They frequent the alleys of damp woods, where they become the prey of theLibellulæ[71]and other carnivorous insects. Their bodies and abdomens are slender, their wings large, thin, fragile, often of a dark colour, with brilliant markings.The caterpillars of theGeometrinæare known by the name of loopers or geometers. We have previously described their singularorganisation. They are continually spinning a silken thread, which keeps them attached to the plant on which they live. If you touch the leaf which supports them they immediately let themselves fall.Fig. 257.—Looper hanging by its thread.Fig. 258.—Seen at the side.Fig. 259.—Front view.Figs. 260 and 261.—Remounting its thread."Nevertheless, they do not generally fall to the ground," says Réaumur; "there is a cord ready to support them in the air (Fig. 257), and a cord which they can lengthen as they will; this cord is only a very thin thread, but has nevertheless strength enough to support the caterpillar (Figs.258,259). All that there seems to fear is, that the thread may lengthen too quickly and the caterpillar fall, rather than descend gently, to the ground. But what we must first remark and admire is, that the caterpillar is mistress of its movements, and is not obliged to descend too quickly; it descends by stages; it stops in the air when it pleases. Generally it only descends at most about one foot at a time, and sometimes only half a foot or a few inches, after which it makes a pause more or less long, as it pleases."It is in this way that the caterpillars let themselves fall from the top of the highest trees: they remount again with no less ease.Let us listen to Réaumur's description of the means employed by this caterpillar to ascend these heights. Figs.260and261, drawn, as the three preceding ones, from the plates in Réaumur's Memoir, help us to follow the explanation given by the illustrious naturalist of the evolutions of our little acrobat:—"To remount," says Réaumur, "the caterpillar seizes the thread between its jaws, as high up as it can; as soon as it has done this it twists its head round, lays it over on one side, and continues to do so more and more every moment. Its head seems to descend below the last of the scaly legs which are on the same side as that to which it is inclined. The truth is, however, that it is not its head which descends, the part of the thread which it holds between its jaws is a fixed point for its head and for the rest of its body; it is that portion of the back corresponding with its scaly legs which the caterpillar twists upwards; the consequence is that the scaly legs and that part of the body to which they belong then ascend. When the last pair of legs is just over the jaws of the caterpillar, one leg, viz., that which is on the side towards which the head is inclined, seizes the thread and brings it over to the corresponding leg on the other side, which is advanced to receive it. If the head is then raised, which is done immediately, it is in order that it may seize the thread at a higher point than that at which it was caught at first; or, which is the same thing, the head, and consequently the whole body of the caterpillar, is found to have ascended to a height equal to the length of the thread which is between the place where its jaws seized it the first time and that where they seized it the second time. The first move in the upward direction is thus made, and the second soon follows.... If you were to seize the caterpillar on its arrival at the end of its upward journey, you would see a packet of threads huddled together between the four hindmost of the scaly legs. The greater the height ascended the greater is the size of this packet. All the turns of the thread which compose it are entangled. So the caterpillar does not consider it of any value. As soon as the insect can walk it gets rid of the mass, sets its legs free, and leaves it behind before one or at most two steps have been taken. The cord is wasted on each ascent, but the caterpillar can afford to lose as many as it likes, for it has in itself the source of the matter necessary for the composition of the thread, and it is a source from which that which was drawn off is being continually re-supplied. Moreover, spinning the thread costs the caterpillars but little; indeed, the loopers economisethis thread so badly that most of them leave it behind them wherever they go."Fig. 262.—Hybernia leucophearia, male.Fig. 262.—Hybernia leucophearia, male.They are found on many trees, but particularly on the oak, the foliage of which they often entirely devour. They burrow into the ground to change into chrysalides, and undergo all their metamorphoses in the course of the year. Others do not become perfect insects till the autumn, or sometimes not even till the following spring. A few assume the perfect state in winter. There are, indeed, some of these, such as the males of theHybernias, which fly about on the foggy evenings of November. The females of this genus have either no wings at all, or else only rudimentary ones. Two species, theHybernia defoliaria, or Winter Moth, and theChimatobia brumata, abundant here, are very common in the environs of Paris.M. Maurice Girard says, in his work on the metamorphoses of insects, that the females of these moths can easily be found at the beginning of November, in a very strange place, namely, on the gas lamps of the public promenades; for instance, along the roads in the Bois de Boulogne. No doubt they had climbed up to this height, attracted by the light, or perhaps had been carried thither by the males, which fly, having wings.Fig. 263.—Winter MothFig. 264.—Winter MothFig. 263.—Winter Moth (Hybernia defoliaria), male.Fig. 264.—Winter Moth (Hybernia defoliaria), female.In February and March appear other analogous species. "We may find," says M. Maurice Girard, "near Paris, in the meadows which surround the confluence of the Seine and the Marne, at theend of the month of March, theNyssia zonaria(Fig. 267), the males of which insect remain during the day motionless on the grass."[72]Fig. 265.—Chimatobia brumata, male.Fig. 266.—Chimatobia brumata, female.Fig. 265.—Chimatobia brumata, male.Fig. 266.—Chimatobia brumata, female.There are some species of this family in which the wings of the females are developed like those of the males.[73]Such are thePeppered Moth (Amphidasis betularia) and the Currant Moth (Abraxas grossulariata), whose caterpillar lives on the red currant and gooseberry, and an immense number known as Thorns, Carpets, Waves, &c.Fig. 267.—Nyssia zonaria, male and female.Fig. 267.—Nyssia zonaria, male and female.The section of thePyralinacontains the smallest nocturnalLepidoptera, and nearly all those tiny species which flutter round our lights in the evening.Fig. 268.—Penthina pruniana.Here are some drawings of a few of the numerous species of this section, remarkable for their small size and beauty:—Penthina pruniana,Ædia pusiella,Xylopoda fabriciana,Pœdisca autumnana,Tortrix roborana,Philobacera fagana,Tortrix sorbiana,Antithesia salicana,Pœdisca occultana,Argyrolepia æneana,Sericoris Zinkenana,Sarrothripa revayana,Cochylis francilana,Choreutes dolosana(Figs. 268 to 281).[74]Fig. 269.—Ædia pusiella.Fig. 269.—Ædia pusiella.Fig. 270.—Xylopoda fabriciana.In a book of this kind we can only mention some types among these last insects, which claim our attention in what we might almost call a tyrannical manner. We will, therefore, content ourselves by saying a few words about the Green Tortrix, the Pyralis of the Vine, the Bee-hive Moth, some species of the Clothes Moth family (Tineina), and finally of theŒcophoræ.Fig. 271.—Pœdisca autumnana.Fig. 272.—Tortrix roborana.Fig. 273.—Philobacera fagana.Fig. 274.—Tortrix sorbiana.The Green Tortrix (Tortrix viridana) has wings of a green colour, with the margin and fringe whitish on the anterior, and of an ashy grey on the posterior wings. The under-side of the four wings is ofa bright white, as if it had been silvered. This pretty moth comes out in the month of May. It is so common everywhere, that at this season it is only necessary to shake the branches of the oaks which border the alleys of the woods to set in motion hundreds of them. The caterpillar is green, with black warty spots, each having a hair of the same colour. They are wonderfully lively, the moment they are disturbed taking refuge in a rolled leaf, which serves them as a dwelling-place. If they are pursued, they let themselves fall by the aid of a thread, and do not re-ascend till they think they can count on repose and security. This, and many kindred species, do a great deal of damage to our trees. They strip them of their leaves, and sometimes give them, during the first days of summer, the sad and melancholy appearance which they present in the middle of winter.Fig. 277.—Argyrolepia æneana.Fig. 275.—Antithesia salicana.Fig. 276.—Pœdisca occultanaFig. 277.—Argyrolepia æneana.Fig. 278.—Sericoris Zinkenana.Fig. 279.—Sarrothripa revayana.Fig. 280.—Cochylis francilana.Fig. 281.—Choreutes dolosana.We have just alluded to the tube formed of a rolled leaf, in which the caterpillar takes refuge, and in which it lives. This tube it constructs itself. Réaumur has devoted a magnificent chapter of hisMemoirs to observations on the skill with which divers species of caterpillars fold, roll, and bind the leaves of plants and trees, especially those of the oak. Let us listen to the great observer:—"If one looks attentively at the leaves of the oak tree towards the middle of the spring, many of them will be seen to be rolled in different ways. The exterior surface of the end of one of these leaves has, it appears, been rolled back towards the interior surface, in order to describe the first turn of a spiral, which is then covered by many other turns (Fig. 282). Some leaves are rolled towards their exterior surfaces, others are rolled towards their interior surfaces, but in a totally different direction. The length or axis of the first roll is perpendicular to the principal rib and to the stalk of the leaf, the axis of the latter parallel to the same rib (Fig. 283). Work of this kind would not be very difficult to perform for those who had fingers; but caterpillars have neither fingers nor anything equivalent to fingers. Moreover, to have rolled the leaves is only to have done half the work: they must be retained in a position from which their natural spring tends constantly to draw them. The mechanism to which the caterpillars have recourse for this second part of their work is easily perceived. We see packets of threads attached by one end to the surface of the roll, and by the other to the flat surface of the leaf.They are so many bands, so many little cords which hold out against the spring of the leaf. There are sometimes more than from ten to twelve of these bands arranged nearly in the self-same straight line. Each band is a packet of threads of white silk, pressed one against the other, and yet we must remember all are separate."[75]Fig. 282.—Oak leaf rolled perpendicularly.Fig. 283.—Oak leaf rolled sideways.Réaumur made the oak-leaf rollers work in his house. He has admirably described all their little manœuvres, but we lack the space to convey to the reader the result of his minute observations. In fact, the leaf-rollers construct for themselves a sort of cylindrical cell, which receives light only through the two extremities. The convenience of this green fresh habitation is, that its walls furnish food to the animal which inhabits it. The caterpillar, thus sheltered, sets to work to gnaw away at the end of the leaf which it rolled first; it then eats all the rolls it has made, up to the very last.Fig. 284.—Leaf of sorrel, a portion of which is cut and rolled perpendicularly to the leaf.Fig. 284.—Leaf of sorrel, a portion of which is cut and rolled perpendicularly to the leaf.Réaumur found also rolls which had been formed of two or three leaves rolled lengthwise, and he saw that the leaves which had occupied the centre had been almost entirely eaten. He saw also caterpillars which continued to eat while they were making their habitation. Let us add that one of the ends of the roll is the opening through which the caterpillar casts its excrement; that the caterpillar can prepare itself a fresh roll if it is turned out of the first; and, lastly, that it is in a rolled leaf that the caterpillar undergoes its metamorphoses into a chrysalis and into a moth.Réaumur studied other leaf-rollers; for instance, those which roll the leaves of nettles and of sorrel. The last one works in a manner which deserves to be mentioned. Its roll is of no particular shape, but it is its position which is remarkable. It is set upon the leaf likea ninepin (Fig. 284). The caterpillar has not only to twist it up into a roll, but also to place it perpendicularly on the leaf.Figs. 285 and 286.—Willow leaves rolled by a caterpillar, and section of a bundle of leaves drawn together by a caterpillar.Next to the rolling caterpillars, let us mention those which are contented with folding the leaves. These caterpillars then lie in a sort of flat box. Besides the rolling and folding caterpillars, there are still those which bind up a good many leaves in one packet. These packets are to be found on nearly every tree and shrub, and the caterpillar, lying nearly in the middle of the packet, is well sheltered, and surrounded by a good supply of food. We will content ourselves bygiving a drawing, after Réaumur, of the pretty arrangement of the leaves of a species of willow (Figs.285,286). In the figures we see the parcel bound together by the caterpillar. In that to the right we see the transverse section of the packet of leaves magnified. At the two edges are seen the threads which keep the leaves together, and the cavity occupied by the caterpillar.The Vine Pyralis is produced from a leaf-rolling caterpillar, which deserves our attention on account of the ravages which it has for some time committed, and which it still commits in vineyards. It was at the end of the sixteenth century that this pyralis first showed itself in the environs of Paris, in the territory of Argenteuil. "The inhabitants of this commune," writes the Abbé Lebœuf, "looked on the insects which spoiled their vines in the spring of 1562 as a visitation of God. The Bishop of Paris gave orders that they should offer up public prayers for the diminution of these insects, and that they should join to their prayers, exorcisms, without leaving the church." Prayers, processions, exorcisms, were again had recourse to in 1629, in 1717, and in 1733, to stop the ravages of this insect among the vines of Colombes, in the territory of Aï.The country of the Mâconnais and the Beaujolais became in their turn the theatre of the ravages of the pyralis. These ravages very soon increased and spread. In 1836, 1837, 1838, this plague raged in the departments of the Saône-et-Loire, of the Rhône, of the Côte-d'Or, of the Marne, of the Seine-et-Oise, of the Charente-Inférieure, of the Haute-Garonne, of the Pyrénées-Orientales, and of the Hérault.To give an idea of the losses which may be occasioned by the pyralis, in a period of ten years (1828-1837), twenty-three communes comprised in the two departments of the Saône-et-Loire and of the Rhône lost 75,000 hectolitres of wine a year, which may be valued at 1,500,000 francs. If we were to calculate the supply of articles of all sorts which this great number of casks of wine would have necessitated, the imposts on their transport, the duty, the taxes levied on their sale, the carriage by land and water, which would have brought receipts into the treasury, and lastly the diminution of taxes which had to be granted for seven years to the vine proprietors in the department of the Saône-et-Loire, and in 1837 in the department of the Rhône, and which amounted to a total of more than 100,000 francs, we shall find that the ravages of the pyralis caused in these two departments an annual loss of 3,408,000 francs, and as the visitation lasted ten years, we get the enormous sum total of 34,000,000 destroyed by the ravages of one species of insect.The moth of the pyralis (Fig. 287) shows itself from the 10th to the 20th of June. It is yellowish, more or less shot with gold. When at rest, its wings are folded back one over the other like a roof. Its flight is of short duration; it contents itself with going from one vine stock to another.Fig. 287.—The Vine Pyralis.Fig. 288.—Caterpillar of the Vine Pyralis.It is at sunset mostly that you see the moths of the pyralis fluttering about. They remain quiet during the day, particularly when the sun is at its hottest. They live on an average for ten days. The females lay their eggs—which are at first green, then yellowish, then brown—on the lower surface of the leaves.Fig. 289.—Chrysalis of the Vine Pyralis.The caterpillar of the pyralis (Fig. 288) is called, in vulgar parlance, according to the different places in which it occurs, vine worm, summer worm, vintage worm, shell. In the south of France it is called, in the patois of Languedoc,babota. Almost immediately after they leave the eggs, the little caterpillars hide themselves in the fissures of the vine stocks or the props which support them. They spin a small cocoon of a greyish silk, in which they remain curled up till the month of May. From the moment the leaves begin todevelop they throw out threads here and there, entangling all the young shoots of the vine, which gives a desolate appearance to thevineyards. The leaves of the vine are their favourite food, but they attack the seeds of the grape also. As they increase in size every day, the damage they do goes on increasing, and has not reached the maximum of intensity till the moment when the caterpillars are about to change into chrysalides. They are then three-quarters of an inch long and of a yellowish green colour.Fig. 290.—The Vine Pyralis in its three states. 1. Leaf with batches of eggs laid upon it. 2. Batches of recently laid eggs. 3. Eggs in which caterpillars can be perceived. 4. Batch of eggs from which the caterpillars have already emerged. 5. Small caterpillars hanging by threads. 6. Leaf with the chrysalis. 7. Caterpillar. 8. Moth.From the 20th of June to the 10th of July they seek shelter in the dry and interlaced leaves which have already served them for places of refuge and partly also for food, or else they make themselves a fresh nest.At the end of two or three days, the caterpillar has become a chrysalis (Fig. 289), which in a short time assumes a brown colour. Shut up in the interior of the cocoon which the caterpillar had spun before undergoing its metamorphosis, it changes into a moth at the end of from fourteen to sixteen days.The best way to diminish the ravages of the pyralis is to pluck off the leaves which are laden with eggs, and burn them, or bury them in deep holes.Fig. 290, which we devote to the conspicuous insect whose destructive history we have been here able to sketch only slightly, gives all the particulars relating to this dangerous guest of the vineyards. On a branch of the vine may be perceived the pyralis in the caterpillar state, the eggs which have been laid by the moths, the chrysalides, and perfect insects. The eggs are shown at two periods of their development.Fig. 291.—Galleria cerella.The Bee-hive or Wax Galleria is to be met with in all countries where bees are reared.The moth (Fig. 291) hides itself during the day round about the bee-hives, and endeavours to make its way into them after sunset. The caterpillar is of a dirty white, with brown warty spots, each surmounted by a fine hair. It lives on wax, twines its threads round the honeycomb, and very soon causes the larvæ contained in it to perish.When it emerges from the egg, which the female has laid in the honeycomb, the caterpillar makes for itself with the wax a round tube, in which it is safe against the stings of the bees. This tube, at first very small, is lengthened and enlarged as the caterpillar increases in size. It is generally from three to five inches in length. It is inthe interior of this that the caterpillar constructs itself a hard cocoon, resembling leather, and it changes into a brownish chrysalis.A species of the genusButalis, theButalisorAlucita granella, is, in certain cantons of France, one of the greatest pests to agriculture. The caterpillar of theTinea granellaundergoes its metamorphosis in the interior of grains of barley and of wheat, which it devours without being perceived from without. The female lays her eggs on the grains of corn before they are ripe. From four to six days after, the eggs are hatched, and the young caterpillars are hardly as thick as a hair. Each one takes possession of a grain of corn, and penetrates into it by an imperceptible opening. They eat the flower without injuring the teguments of the grain.
Fig. 231.—Attacus (Bombyx) Atlas.Fig. 231.—Attacus (Bombyx) Atlas.
Fig. 232.—The Lackey (Bombyx neustria).
One part ofFig. 233shows the arrangement of the caterpillars on coming out of the nest. These caterpillars are furnished with long hairs, slightly tufted, which come off with the greatest ease, and which if they penetrate into the skin, cause violent itching. In 1865 a number of the alleys of the Bois de Boulogne were shut up from the public in order to save them from this annoyance. These caterpillars construct a covering common to them all, in which they live, and transform themselves therein, each insect making for his own private use a small cocoon. This insect is said to have been found in England, but there is not sufficient evidence to admit it into our lists.
Fig. 233.—Larvæ of the Procession MothFig. 233.—Larvæ of the Procession Moth (Bombyx processionea).
Fig. 234.—The Vapourer Moth (Orgyia antiqua), male and female.
TheOrgyiascomprise a great number of small species, of a dark colour, which do a great deal of damage to our forest trees. In September and October the male of theOrgyia antiqua, with his tawny wings, may often be seen flying about the streets of London. The female (Fig. 234) is remarkable, as she has only the rudiments of wings, and only goes as far as the side of her cocoon. The caterpillar of theOrgyia pudibunda, called also the Hop Dog, attacks almost every sort of tree. When the state of the atmosphere favours their propagation, they appear in fearful quantities, and cause the greatest havoc. During the autumn of 1828, in the environs of Phalsbourg, they were to be counted by millions. The extent of the woods laid waste was calculated at about fifteen hundred hectares. It is common in this country.
Fig. 235.—Orgyia pudibunda.
Among the genusLiparis, the species of which are also very destructive to trees, we must mention the Brown-tailed Moth (Liparis chrysorrhœa,Fig. 236), a species by no means rare in England. Thecaterpillars live in quantities, on apple, pear, and elm trees, and destroy the plantations of the promenades of Paris.
Fig. 236.—Liparis chrysorrhœa.
The females of this genus tear off the fur from the extremity of their abdomens to make a soft bed for their eggs, and to preserve them from the cold. And yet they are never to see their young, for they die after they have laid their eggs. Another tribe ofBombycinacontains species of a small size, which are remarkable from the habits of their caterpillars, which make, with foreign bodies, cases, in the interior of which they live and undergo their metamorphoses.
The caterpillars of the genusPsychelive in a case composed of fragments of leaves, of bits of grass and straw, of small sticks of wood, or of little stones, stuck together, and intermixed with silky threads.
VII.—The Goat-moth (Cossus ligniperda). Larva, pupa, and perfect insect.1, 2. Perfect insect. 3. Pupa. 4. Larva.
We give a representation (in Figs.237,239, and240) of the cases of the caterpillars of three different kinds. The females of these moths are completely destitute of wings, and resemble caterpillars. As a general rule they hardly ever leave their case. The males (Figs.238,242) are of a blackish grey, and fly very swiftly.
The caterpillars of the genusHepialusare difficult to observe, as they live in the interior of the roots of various vegetables. Such is the common Ghost Moth (Hepialus humuli), which sometimes causes the greatest damage.
Fig. 243.—Zeuzera æsculi.Fig. 243.—Zeuzera æsculi.
The type of the genusZeuzeraisZeuzera æsculi, or Wood Leopard (Fig. 243). It has white wings with large blackish blue spots on the anterior, and small black spots on the posterior wings. The caterpillar, of a vivid yellow, spotted with black, lives in the interior of the trunks of a great many trees, principally the chestnut, the elm, the lime, and the pear tree. This moth, which is known also by the name of Coquette, is to be seen in the evening flying about the public gardens of Paris, and is not rare in England. The most celebrated species of the allied genusCossusis the Wood-boring Goat Moth (Cossus ligniperda), figured in theopposite plate. The moth has a heavy brownish body and greyish wings streaked with black. It is found in most parts of Europe. The caterpillar is of a reddish colour, as if it had on a leathern jerkin, and disgorges a liquid which is believed to soften ligneous fibres, and it lives in the interiorof willows and other trees. It was on this caterpillar that Lyonnet made his admirable anatomical researches.
Fig. 244.—Larva of Dicranura vinula.
Fig. 245.—Dicranura vinula.
Another tribe ofBombycinacomprises some very strange caterpillars, whose hindermost feet are changed into forked prolongations, which they move about in a threatening manner. These sort of fly-traps are perhaps meant to keep at a distance those insects which would lay their eggs upon the caterpillar's body. The caterpillarsofDicranuraare of this kind. We give a representation of the caterpillar and the moth of the Puss Moth (Dicranura vinula, Figs.244,245), as also the moth of theDicranura verbasci, the former of which is common in England, and the larva may be found during the late summer and early autumn feeding on poplars and willows; and of the caterpillar ofStauropus fagi, the Lobster Moth (Fig. 247), rare in France, whose appearance is strange indeed. The moths, on the contrary, have nothing about them remarkable.
Fig. 246.—Dicranura verbasci.
Fig. 247.—Larva of the Lobster Moth (Stauropus fagi).
TheNoctuinaare a group of Lepidoptera of middling size, and generally found in woods, meadows, and gardens, where their caterpillars have lived. They seldom fly till about sunset, or during the night. Their upper wings are of a dark colour, with spots in the middle of a particular shape. Their lower wings are of various colours, often whitish, sometimes red or yellow.
Fig. 248.—Noctua tegamon.
Fig. 249.—Noctua nebulosa.
We give representations of some of the species of this group.[69]Noctua tegamon,Fig. 248;Noctua nebulosa,Fig. 249;Noctua musiva,Fig. 250;Noctua brunnea,Fig. 251;Catocala fraxini,Fig. 252;Catocala Americana,Fig. 253;Catocala paranympha,Fig. 254;Catocala nupta,Fig. 255, the Red Underwing; andErebus strix,Fig. 256.
Fig. 250.—Noctua musiva.
Fig. 251.—Noctua brunnea.
The bodies of these moths are robust and sometimes massive, and are scaly rather than woolly. The thorax is sometimes bristling with hairy tufts.
This genus includes 800 species, of which there are about 300 in France. The caterpillars of theNoctuinaare smooth orvery slightly covered with hair, usually of a pale colour, and live on low plants, of which they devour, some the leaves, others the roots; then it is they are most destructive to agriculture. There are some of them which eat any caterpillars they may chance to meet, and even those of their own species, leaving nothing but the skin. Some of them surround themselves with a light cocoon before becoming chrysalides; others bury themselves in soft, well-pulverised soil.
Fig. 252.—Catocala fraxini.
Fig. 253.—Catocala Americana.
Fig. 254.—Catocala paranympha.
Fig. 255.—Catocala nupta.
Fig. 256.—Erebus strix.
The family ofGeometrinæ, or Geometers, comprises moths of a middling size, and usually flying after sunset and during the night.[70]They frequent the alleys of damp woods, where they become the prey of theLibellulæ[71]and other carnivorous insects. Their bodies and abdomens are slender, their wings large, thin, fragile, often of a dark colour, with brilliant markings.
The caterpillars of theGeometrinæare known by the name of loopers or geometers. We have previously described their singularorganisation. They are continually spinning a silken thread, which keeps them attached to the plant on which they live. If you touch the leaf which supports them they immediately let themselves fall.
"Nevertheless, they do not generally fall to the ground," says Réaumur; "there is a cord ready to support them in the air (Fig. 257), and a cord which they can lengthen as they will; this cord is only a very thin thread, but has nevertheless strength enough to support the caterpillar (Figs.258,259). All that there seems to fear is, that the thread may lengthen too quickly and the caterpillar fall, rather than descend gently, to the ground. But what we must first remark and admire is, that the caterpillar is mistress of its movements, and is not obliged to descend too quickly; it descends by stages; it stops in the air when it pleases. Generally it only descends at most about one foot at a time, and sometimes only half a foot or a few inches, after which it makes a pause more or less long, as it pleases."It is in this way that the caterpillars let themselves fall from the top of the highest trees: they remount again with no less ease.
Let us listen to Réaumur's description of the means employed by this caterpillar to ascend these heights. Figs.260and261, drawn, as the three preceding ones, from the plates in Réaumur's Memoir, help us to follow the explanation given by the illustrious naturalist of the evolutions of our little acrobat:—"To remount," says Réaumur, "the caterpillar seizes the thread between its jaws, as high up as it can; as soon as it has done this it twists its head round, lays it over on one side, and continues to do so more and more every moment. Its head seems to descend below the last of the scaly legs which are on the same side as that to which it is inclined. The truth is, however, that it is not its head which descends, the part of the thread which it holds between its jaws is a fixed point for its head and for the rest of its body; it is that portion of the back corresponding with its scaly legs which the caterpillar twists upwards; the consequence is that the scaly legs and that part of the body to which they belong then ascend. When the last pair of legs is just over the jaws of the caterpillar, one leg, viz., that which is on the side towards which the head is inclined, seizes the thread and brings it over to the corresponding leg on the other side, which is advanced to receive it. If the head is then raised, which is done immediately, it is in order that it may seize the thread at a higher point than that at which it was caught at first; or, which is the same thing, the head, and consequently the whole body of the caterpillar, is found to have ascended to a height equal to the length of the thread which is between the place where its jaws seized it the first time and that where they seized it the second time. The first move in the upward direction is thus made, and the second soon follows.... If you were to seize the caterpillar on its arrival at the end of its upward journey, you would see a packet of threads huddled together between the four hindmost of the scaly legs. The greater the height ascended the greater is the size of this packet. All the turns of the thread which compose it are entangled. So the caterpillar does not consider it of any value. As soon as the insect can walk it gets rid of the mass, sets its legs free, and leaves it behind before one or at most two steps have been taken. The cord is wasted on each ascent, but the caterpillar can afford to lose as many as it likes, for it has in itself the source of the matter necessary for the composition of the thread, and it is a source from which that which was drawn off is being continually re-supplied. Moreover, spinning the thread costs the caterpillars but little; indeed, the loopers economisethis thread so badly that most of them leave it behind them wherever they go."
Fig. 262.—Hybernia leucophearia, male.Fig. 262.—Hybernia leucophearia, male.
They are found on many trees, but particularly on the oak, the foliage of which they often entirely devour. They burrow into the ground to change into chrysalides, and undergo all their metamorphoses in the course of the year. Others do not become perfect insects till the autumn, or sometimes not even till the following spring. A few assume the perfect state in winter. There are, indeed, some of these, such as the males of theHybernias, which fly about on the foggy evenings of November. The females of this genus have either no wings at all, or else only rudimentary ones. Two species, theHybernia defoliaria, or Winter Moth, and theChimatobia brumata, abundant here, are very common in the environs of Paris.
M. Maurice Girard says, in his work on the metamorphoses of insects, that the females of these moths can easily be found at the beginning of November, in a very strange place, namely, on the gas lamps of the public promenades; for instance, along the roads in the Bois de Boulogne. No doubt they had climbed up to this height, attracted by the light, or perhaps had been carried thither by the males, which fly, having wings.
In February and March appear other analogous species. "We may find," says M. Maurice Girard, "near Paris, in the meadows which surround the confluence of the Seine and the Marne, at theend of the month of March, theNyssia zonaria(Fig. 267), the males of which insect remain during the day motionless on the grass."[72]
There are some species of this family in which the wings of the females are developed like those of the males.[73]Such are thePeppered Moth (Amphidasis betularia) and the Currant Moth (Abraxas grossulariata), whose caterpillar lives on the red currant and gooseberry, and an immense number known as Thorns, Carpets, Waves, &c.
Fig. 267.—Nyssia zonaria, male and female.Fig. 267.—Nyssia zonaria, male and female.
The section of thePyralinacontains the smallest nocturnalLepidoptera, and nearly all those tiny species which flutter round our lights in the evening.
Fig. 268.—Penthina pruniana.
Here are some drawings of a few of the numerous species of this section, remarkable for their small size and beauty:—Penthina pruniana,Ædia pusiella,Xylopoda fabriciana,Pœdisca autumnana,Tortrix roborana,Philobacera fagana,Tortrix sorbiana,Antithesia salicana,Pœdisca occultana,Argyrolepia æneana,Sericoris Zinkenana,Sarrothripa revayana,Cochylis francilana,Choreutes dolosana(Figs. 268 to 281).[74]
In a book of this kind we can only mention some types among these last insects, which claim our attention in what we might almost call a tyrannical manner. We will, therefore, content ourselves by saying a few words about the Green Tortrix, the Pyralis of the Vine, the Bee-hive Moth, some species of the Clothes Moth family (Tineina), and finally of theŒcophoræ.
The Green Tortrix (Tortrix viridana) has wings of a green colour, with the margin and fringe whitish on the anterior, and of an ashy grey on the posterior wings. The under-side of the four wings is ofa bright white, as if it had been silvered. This pretty moth comes out in the month of May. It is so common everywhere, that at this season it is only necessary to shake the branches of the oaks which border the alleys of the woods to set in motion hundreds of them. The caterpillar is green, with black warty spots, each having a hair of the same colour. They are wonderfully lively, the moment they are disturbed taking refuge in a rolled leaf, which serves them as a dwelling-place. If they are pursued, they let themselves fall by the aid of a thread, and do not re-ascend till they think they can count on repose and security. This, and many kindred species, do a great deal of damage to our trees. They strip them of their leaves, and sometimes give them, during the first days of summer, the sad and melancholy appearance which they present in the middle of winter.
We have just alluded to the tube formed of a rolled leaf, in which the caterpillar takes refuge, and in which it lives. This tube it constructs itself. Réaumur has devoted a magnificent chapter of hisMemoirs to observations on the skill with which divers species of caterpillars fold, roll, and bind the leaves of plants and trees, especially those of the oak. Let us listen to the great observer:—"If one looks attentively at the leaves of the oak tree towards the middle of the spring, many of them will be seen to be rolled in different ways. The exterior surface of the end of one of these leaves has, it appears, been rolled back towards the interior surface, in order to describe the first turn of a spiral, which is then covered by many other turns (Fig. 282). Some leaves are rolled towards their exterior surfaces, others are rolled towards their interior surfaces, but in a totally different direction. The length or axis of the first roll is perpendicular to the principal rib and to the stalk of the leaf, the axis of the latter parallel to the same rib (Fig. 283). Work of this kind would not be very difficult to perform for those who had fingers; but caterpillars have neither fingers nor anything equivalent to fingers. Moreover, to have rolled the leaves is only to have done half the work: they must be retained in a position from which their natural spring tends constantly to draw them. The mechanism to which the caterpillars have recourse for this second part of their work is easily perceived. We see packets of threads attached by one end to the surface of the roll, and by the other to the flat surface of the leaf.They are so many bands, so many little cords which hold out against the spring of the leaf. There are sometimes more than from ten to twelve of these bands arranged nearly in the self-same straight line. Each band is a packet of threads of white silk, pressed one against the other, and yet we must remember all are separate."[75]
Réaumur made the oak-leaf rollers work in his house. He has admirably described all their little manœuvres, but we lack the space to convey to the reader the result of his minute observations. In fact, the leaf-rollers construct for themselves a sort of cylindrical cell, which receives light only through the two extremities. The convenience of this green fresh habitation is, that its walls furnish food to the animal which inhabits it. The caterpillar, thus sheltered, sets to work to gnaw away at the end of the leaf which it rolled first; it then eats all the rolls it has made, up to the very last.
Fig. 284.—Leaf of sorrel, a portion of which is cut and rolled perpendicularly to the leaf.Fig. 284.—Leaf of sorrel, a portion of which is cut and rolled perpendicularly to the leaf.
Réaumur found also rolls which had been formed of two or three leaves rolled lengthwise, and he saw that the leaves which had occupied the centre had been almost entirely eaten. He saw also caterpillars which continued to eat while they were making their habitation. Let us add that one of the ends of the roll is the opening through which the caterpillar casts its excrement; that the caterpillar can prepare itself a fresh roll if it is turned out of the first; and, lastly, that it is in a rolled leaf that the caterpillar undergoes its metamorphoses into a chrysalis and into a moth.
Réaumur studied other leaf-rollers; for instance, those which roll the leaves of nettles and of sorrel. The last one works in a manner which deserves to be mentioned. Its roll is of no particular shape, but it is its position which is remarkable. It is set upon the leaf likea ninepin (Fig. 284). The caterpillar has not only to twist it up into a roll, but also to place it perpendicularly on the leaf.
Figs. 285 and 286.—Willow leaves rolled by a caterpillar, and section of a bundle of leaves drawn together by a caterpillar.
Next to the rolling caterpillars, let us mention those which are contented with folding the leaves. These caterpillars then lie in a sort of flat box. Besides the rolling and folding caterpillars, there are still those which bind up a good many leaves in one packet. These packets are to be found on nearly every tree and shrub, and the caterpillar, lying nearly in the middle of the packet, is well sheltered, and surrounded by a good supply of food. We will content ourselves bygiving a drawing, after Réaumur, of the pretty arrangement of the leaves of a species of willow (Figs.285,286). In the figures we see the parcel bound together by the caterpillar. In that to the right we see the transverse section of the packet of leaves magnified. At the two edges are seen the threads which keep the leaves together, and the cavity occupied by the caterpillar.
The Vine Pyralis is produced from a leaf-rolling caterpillar, which deserves our attention on account of the ravages which it has for some time committed, and which it still commits in vineyards. It was at the end of the sixteenth century that this pyralis first showed itself in the environs of Paris, in the territory of Argenteuil. "The inhabitants of this commune," writes the Abbé Lebœuf, "looked on the insects which spoiled their vines in the spring of 1562 as a visitation of God. The Bishop of Paris gave orders that they should offer up public prayers for the diminution of these insects, and that they should join to their prayers, exorcisms, without leaving the church." Prayers, processions, exorcisms, were again had recourse to in 1629, in 1717, and in 1733, to stop the ravages of this insect among the vines of Colombes, in the territory of Aï.
The country of the Mâconnais and the Beaujolais became in their turn the theatre of the ravages of the pyralis. These ravages very soon increased and spread. In 1836, 1837, 1838, this plague raged in the departments of the Saône-et-Loire, of the Rhône, of the Côte-d'Or, of the Marne, of the Seine-et-Oise, of the Charente-Inférieure, of the Haute-Garonne, of the Pyrénées-Orientales, and of the Hérault.
To give an idea of the losses which may be occasioned by the pyralis, in a period of ten years (1828-1837), twenty-three communes comprised in the two departments of the Saône-et-Loire and of the Rhône lost 75,000 hectolitres of wine a year, which may be valued at 1,500,000 francs. If we were to calculate the supply of articles of all sorts which this great number of casks of wine would have necessitated, the imposts on their transport, the duty, the taxes levied on their sale, the carriage by land and water, which would have brought receipts into the treasury, and lastly the diminution of taxes which had to be granted for seven years to the vine proprietors in the department of the Saône-et-Loire, and in 1837 in the department of the Rhône, and which amounted to a total of more than 100,000 francs, we shall find that the ravages of the pyralis caused in these two departments an annual loss of 3,408,000 francs, and as the visitation lasted ten years, we get the enormous sum total of 34,000,000 destroyed by the ravages of one species of insect.The moth of the pyralis (Fig. 287) shows itself from the 10th to the 20th of June. It is yellowish, more or less shot with gold. When at rest, its wings are folded back one over the other like a roof. Its flight is of short duration; it contents itself with going from one vine stock to another.
It is at sunset mostly that you see the moths of the pyralis fluttering about. They remain quiet during the day, particularly when the sun is at its hottest. They live on an average for ten days. The females lay their eggs—which are at first green, then yellowish, then brown—on the lower surface of the leaves.
Fig. 289.—Chrysalis of the Vine Pyralis.
The caterpillar of the pyralis (Fig. 288) is called, in vulgar parlance, according to the different places in which it occurs, vine worm, summer worm, vintage worm, shell. In the south of France it is called, in the patois of Languedoc,babota. Almost immediately after they leave the eggs, the little caterpillars hide themselves in the fissures of the vine stocks or the props which support them. They spin a small cocoon of a greyish silk, in which they remain curled up till the month of May. From the moment the leaves begin todevelop they throw out threads here and there, entangling all the young shoots of the vine, which gives a desolate appearance to thevineyards. The leaves of the vine are their favourite food, but they attack the seeds of the grape also. As they increase in size every day, the damage they do goes on increasing, and has not reached the maximum of intensity till the moment when the caterpillars are about to change into chrysalides. They are then three-quarters of an inch long and of a yellowish green colour.
Fig. 290.—The Vine Pyralis in its three states. 1. Leaf with batches of eggs laid upon it. 2. Batches of recently laid eggs. 3. Eggs in which caterpillars can be perceived. 4. Batch of eggs from which the caterpillars have already emerged. 5. Small caterpillars hanging by threads. 6. Leaf with the chrysalis. 7. Caterpillar. 8. Moth.
From the 20th of June to the 10th of July they seek shelter in the dry and interlaced leaves which have already served them for places of refuge and partly also for food, or else they make themselves a fresh nest.
At the end of two or three days, the caterpillar has become a chrysalis (Fig. 289), which in a short time assumes a brown colour. Shut up in the interior of the cocoon which the caterpillar had spun before undergoing its metamorphosis, it changes into a moth at the end of from fourteen to sixteen days.
The best way to diminish the ravages of the pyralis is to pluck off the leaves which are laden with eggs, and burn them, or bury them in deep holes.
Fig. 290, which we devote to the conspicuous insect whose destructive history we have been here able to sketch only slightly, gives all the particulars relating to this dangerous guest of the vineyards. On a branch of the vine may be perceived the pyralis in the caterpillar state, the eggs which have been laid by the moths, the chrysalides, and perfect insects. The eggs are shown at two periods of their development.
Fig. 291.—Galleria cerella.
The Bee-hive or Wax Galleria is to be met with in all countries where bees are reared.
The moth (Fig. 291) hides itself during the day round about the bee-hives, and endeavours to make its way into them after sunset. The caterpillar is of a dirty white, with brown warty spots, each surmounted by a fine hair. It lives on wax, twines its threads round the honeycomb, and very soon causes the larvæ contained in it to perish.
When it emerges from the egg, which the female has laid in the honeycomb, the caterpillar makes for itself with the wax a round tube, in which it is safe against the stings of the bees. This tube, at first very small, is lengthened and enlarged as the caterpillar increases in size. It is generally from three to five inches in length. It is inthe interior of this that the caterpillar constructs itself a hard cocoon, resembling leather, and it changes into a brownish chrysalis.
A species of the genusButalis, theButalisorAlucita granella, is, in certain cantons of France, one of the greatest pests to agriculture. The caterpillar of theTinea granellaundergoes its metamorphosis in the interior of grains of barley and of wheat, which it devours without being perceived from without. The female lays her eggs on the grains of corn before they are ripe. From four to six days after, the eggs are hatched, and the young caterpillars are hardly as thick as a hair. Each one takes possession of a grain of corn, and penetrates into it by an imperceptible opening. They eat the flower without injuring the teguments of the grain.