Part 23
If the Mole Crickets, or _Courtilières_, have spades on their front legs, their hind-legs are very little developed, so that it would be perfectly impossible for them to jump, particularly as their large abdomen would hinder their so doing. The wings are broad, and fold back in the form of a fan; they make little use of them, and it is only at night-fall that the mole cricket is seen to disport himself, describing curves of no great height in the air. It is found principally in cultivated land, kitchen-gardens, nursery gardens, wheat fields, &c., where it scoops out for itself an oval cavity communicating with the surface by a vertical hole (Fig. 306). On this hole abut numerous horizontal galleries, more or less inclined, which permit the insect to gain its retreat by a great many roads, when pursued.
It is easy to understand that an insect which undermines land in this way must cause great damage to cultivation. Whether the crops serve it for food or not, they are not the less destroyed by its underground burrowings. Lands infested by the mole cricket are recognisable by the colour of the vegetation, which is yellow and withered; and the rubbish which these miners heap up at the side of the openings leading to their galleries, resembling mole-hills in miniature, betray their presence to the farmer. To destroy them, they pour water or other liquids into their nests, or else they bury, at different distances, vessels filled with water, in which they drown themselves. From the month of April the males betake themselves to the entrance of their burrows, and make their cry of appeal. Their notes are slow, vibrating, and monotonous, and repeated for a long time without interruption, and somewhat resembling the cry of the owl or the goat-sucker.
The female lays her eggs, to the number of from two to three hundred, in the interior of a sort of chamber scooped out in soil stiff enough to resist the action of rain. The hatching takes place at the end of a month.
It is not till the following spring that the larvæ pass into the pupa state, and that the organs of flight begin to be marked out. According to M. Féburier, three years are required for the complete development of the mole cricket, which is a fact that indicates remarkable longevity in these insects. All authors agree, moreover, in extolling the solicitude with which the mole cricket takes care of her little ones. She watches over them, and, they say, procures them food.
The genus _Tridactylus_, which bears a great analogy to the mole cricket, is the smallest genus of Orthoptera known; the species are not more than a sixth of an inch in length, and are found in the south of France, on the banks of the Rhône and other rivers, where they disport themselves in sand exposed to the sun. The _Tridactyli_ leap with remarkable agility, even on the surface of the water, for their legs are provided with flat appendages much resembling battledores.
The Grasshoppers and Locusts take much longer leaps than the Crickets, owing to the conformation of their hind-legs, and they often make use of their wings also, which are very fully developed. These insects are unable to walk, on account of the disproportion which exists between their different pairs of legs. The female is provided with a curved ovipositor with two valves, which serves for breaking up the ground for the reception of its eggs. The male produces a sharp stridulation or screeching sound, by rubbing the cases of its wings--which are furnished with plates which might be compared to cymbals--one against another.
The song of the grasshopper, known by everyone, is a monotonous "zic-zic-zic," which can be heard during the day in grassy places. It is on account of this song that the name of Cigale is sometimes given, though wrongly, to the great green grasshopper. As we have already said in speaking of the Cigale, it is the green grasshopper which La Fontaine had in view in his fable of _La Cigale et la Fourmi_, for all the plates which ornament the ancient editions of the fables of this author represent a grasshopper, and not a Cigale. Grasshoppers are spread over the whole surface of the earth, but are to be met with chiefly in South America, which contains nearly three-fourths of the species known. The European species, on the contrary, are few.
Their habits resemble those of the other herbivorous Orthoptera. They live in meadows, on trees, devouring the leaves and stalks of plants; but they are never found in such great numbers as to cause damage at all to be compared to that caused by the locust. They appear in the month of July and disappear at the beginning of the cold weather. Towards the end of summer their song is heard in the meadows and wheat fields. The females, summoned by the males, are not long in coupling and laying their eggs, which do not hatch until the following spring, in the ground. After four months the larvæ change into pupæ, which already show rudimentary wings, and which by a fifth month pass into the perfect state.
The Great Green Grasshopper (_Locusta viridissima_) is very common in Europe. It remains during the day on trees, and in the evening disports itself in the fields.
The _Decticus verrucivorus_ (Fig. 307) is a shorter and more thick-set species, whose distinctive feature is a very broad head. Its colour is grey of various shades, and it is to be heard singing during the day in fields of ripe wheat. The name comes from the use made of it by the peasants in Sweden and Germany as a cure for warts.
"The peasants," says Charles de Geer, "make these locusts bite the warts which they often have on their hands, and the liquid which at the same time flows from the insect's mouth into the wound causes the warts to dry up and disappear. It is for this reason they have given them the name of Wart-bit or Wart-biter."
The _Phaneropteræ_ and the _Copiphores_ are exotic Locusts. The _Ephippigeræ_ are small species whose thorax, which is very convex, resembles a saddle.
One often meets in the environs of Paris the Vine Ephippiger (_Ephippigera vitium_), which is greenish, with four brown stripes on its head. In this species the wing cases, or elytra, are almost obsolete, and the wings are reduced to mere arched scales, whose friction produces a stridulation or screeching noise. The females are provided with a similar apparatus, so that they perform duets.[78]
[78] The species of genus _Saga_ sometimes reach extraordinary dimensions. Thus, in 1863, there was found in Syria, after a shower of ordinary locusts, a specimen of the _Saga_ which was three inches and a quarter long. It was presented to the Museum of Natural History of Paris, by M. L. Delair.
The genus _Gryllacris_ resembles the crickets. It contains the _Anostostomæ_ of New Holland, which are said to be destitute of wings, even in the perfect state.
We arrive now at the redoubtable tribe of _Acridium_, or Locust, whose fearful ravages are so well known.
These are, among the Orthoptera, the best adapted for jumping. The thigh and the leg, folded together when at rest, are stretched out suddenly under the action of very powerful muscles. The body, resting then on the tarsi and on the flexible spines of the legs, is shot into the air to a great height. They fly very well, but the power of walking and running is denied to them, as it is also to the other _Saltatoriæ_. The females have no ovipositor. This peculiarity, and the formation of their antennæ, which are very short, distinguish the locusts from the grasshoppers.
The males, as we have already said, make a shrill stridulation by rubbing their thighs over their elytra. There is never more than one thigh in motion at a time; the insect using the right and the left by turns. The sound is made stronger by a sort of drum filled with air, and covered with a very thin skin, which is found on each side of the body, at the base of the abdomen. The locust's song is less monotonous than that of the grasshopper. It is capable of much variation; it is a noise just like that of a rattle, but with sounds which vary very much, according to the species.
They move about by day, frequent dry places, and are very fond of sitting on the grass in the sun. Certain species, which inhabit the warm regions of the south, move their legs with scarcely any noise; it being only perceptible to a very fine ear.
Locusts are very abundant in many parts of the world. In northern countries, where they multiply less rapidly, their ravages are less disastrous, though still very considerable. But in the southern portions of the globe they are a perfect pest--the eighth plague of Egypt. Certain species multiply in such a prodigious manner, that they lay waste vast spaces of land, and in a very short time reduce whole countries to the very last state of misery. These insects inflate themselves with air, and undertake journeys during which they travel more than six leagues a day, laying waste all vegetation on their road.
The most destructive species is the Migratory Locust (_Acridium_ [or _OEdipoda_] _migratorium_, Fig. 308), which is very common in Africa, India, and throughout the whole of the East. Isolated specimens of this insect are to be found in the meadows round about Paris, especially towards the end of the summer, and, very rarely, in England. This species is greenish, with transparent elytra of a dirty grey, whitish wings, and pink legs. A second species, the Italian locust, also does a great deal of damage in the south. All the species undergo five moults, which take six weeks each. The last takes place at the end of the hot weather, towards the autumn.
It is especially in warm climates that they become such fearful pests to agriculture. Wherever they alight, they change the most fertile country into an arid desert. They are seen coming in innumerable bands, which, from afar, have the appearance of stormy clouds, even hiding the sun. As far and as wide as the eye can reach the sky is black, and the soil is inundated with them. The noise of these millions of wings may be compared to the sound of a cataract. When this fearful army alights upon the ground, the branches of the trees break, and in a few hours, and over an extent of many leagues, all vegetation has disappeared, the wheat is gnawed to its very roots, the trees are stripped of their leaves. Everything has been destroyed, gnawed down, and devoured. When nothing more is left, the terrible host rises, as if in obedience to some given signal, and takes its departure, leaving behind it despair and famine. It goes to look for fresh food--seeking whom, or rather in this case, what it may devour! (PLATE VIII.)
During the year succeeding that in which a country has been devastated by showers of locusts, damage from these insects is the less to be feared; for it happens often that after having ravaged everything, they die of hunger before the laying season begins. But their death becomes the cause of a greater evil. Their innumerable carcases, lying in heaps and heated by the sun, are not long in entering into a state of putrefaction; epidemic disease, caused by the poisonous gases emanating from them, soon break out, and decimate the populations. These locusts are bred in the deserts of Arabia and Tartary, and the east winds carry them into Africa and Europe. Ships in the eastern parts of the Mediterranean are sometimes covered with them at a great distance from the land.
It is related in the Bible, in the tenth chapter of Exodus, that Jehovah commanded Moses to stretch forth his hand to make locusts (Arbeth) come over the whole land of Egypt as the eighth plague, destined to intimidate Pharaoh, who had rebelled against Him. These insects arrived, brought by an east wind, and covered the surface of the country to such a degree that the air was darkened by them.[79]
[79] "And Moses stretched forth his rod over the land of Egypt, and the Lord brought an east wind upon the land all that day, and all that night; and when it was morning, the east wind brought the locusts. And the locusts went up over all the land of Egypt, and rested in all the coasts of Egypt: very grievous were they; before them there were no such locusts as they, neither after them shall be such. For they covered the face of the whole earth, so that the land was darkened; and they did eat every herb of the land, and all the fruit of the trees which the hail had left; and there remained not any green thing in the trees, or in the herbs of the field, through all the land of Egypt."--EXOD. x. 13-15.
They ate up all the herbs of the field and all the fruit of the trees which the hail (the seventh plague) had left. A west wind swept them away again, when Pharaoh had at last promised to allow the children of Israel to depart.
Pliny relates that in many places in Greece a law obliged the inhabitants to wage war against the locusts three times a year; that is to say, in their three states of egg, larva, and adult. In the Isle of Lemnos the citizens had to pay as taxes so many measures of locusts. In the year 170 before our era they devastated the environs of Capua. In the year of our Lord 181 they committed great ravages in the north of Italy and in Gaul. In 1690 locusts arrived in Poland and Lithuania by three different ways, and, as it were, in three different bodies. "They were to be found in certain places where they had died," writes the Abbé Ussaris, an eye-witness, "lying on one another in heaps of four feet in height. Those which were alive, perched upon the trees, bending their branches to the ground, so great was their number. The people thought that they had Hebrew letters on their wings. A rabbi professed to be able to read on them words which signified God's wrath. The rains killed these insects: they infected the air; and the cattle, which ate them in the grass, died immediately."
In 1749 locusts stopped the army of Charles XII., King of Sweden, as it was retreating from Bessarabia, on its defeat at Pultowa. The king thought that he was assailed by a hail-storm, when a host of these insects beat violently against his army as it was passing through a defile, so that men and horses were blinded by this living hail, falling from a cloud which hid the sun. The arrival of the locusts had been announced by a whistling sound like that which precedes a tempest; and the noise of their flight quite over-powered the noise made by the Black Sea. All the country round about was soon laid waste on their route. During the same year a great part of Europe was invaded by these pests, the newspapers of the day being full of accounts relating to this public calamity. In 1753 Portugal was attacked by them. This was the year of the earthquake of Lisbon, and all sorts of plagues seemed at this time to rage in that unfortunate country.
In 1780, in Transylvania, their ravages assumed such gigantic proportions that it was found necessary to call in the assistance of the army. Regiments of soldiers gathered them together and enclosed them in sacks. Fifteen hundred persons were employed in crushing, burying, and burning them; but, in spite of all this, their number did not seem to diminish; but a cold wind, which fortunately sprang up, caused them to disappear. In the following spring the plague broke out again, and every one turned out to fight against it. The locusts were swept with great brooms into ditches, in which they were then burnt; not, however, before they had ruined the whole country. Locusts showed themselves at the same time in the empire of Morocco, where they caused a fearful famine. The poor were to be seen wandering on all sides, digging up the roots of vegetables, and eagerly devouring camels' dung, in hopes of finding in it a few undigested grains of barley.
Barrow and Levaillant, in their travels through Central Africa, speak of similar calamities having happened many times between 1784 and 1797. They add that the surface of the rivers was then hidden by the bodies of the locusts, which covered the whole country.
According to Jackson, in 1739 they covered the whole surface of the ground from Tangiers to Mogador. All the region near to the Sahara was ravaged, whilst on the other side of the river El Klos there was not one of these insects. When the wind blew they were driven into the sea, and their carcases occasioned a plague which laid Barbary waste.
India and China often suffer from these destructive insects. In 1735 clouds of locusts hid from the Chinese both the sun and moon. Not only the standing crops, but also the corn in the barns and the clothes in the houses were devoured.
In the south of France locusts multiply sometimes so prodigiously that in a very short time many barrels may be filled with their eggs. They have caused, at different periods, immense damage. It was chiefly in the years 1613, 1805, 1820, 1822, 1824, 1825, 1832, and 1834, that their visits to the south of France were most formidable.
Mézeray relates that in the month of January, 1613, in the reign of Louis XIII., locusts invaded the country around Arles. In seven or eight hours the wheat and crops were devoured to the roots over an extent of country of 15,000 acres. They then crossed over the Rhine, and visited Tarascon and Beaucaire, where they ate the vegetables and lucerne. They then shifted their quarters to Aramon, to Monfrin, to Valabregues, &c., where they were fortunately destroyed in great part by the starlings and other insect-eating birds, which flocked in innumerable numbers to this game.
The consuls of Arles and of Marseilles caused the eggs to be collected. Arles spent, for this object, 25,000 francs, and Marseilles 20,000 francs. Three thousand quintals of eggs were interred or thrown into the Rhône. If we count 1,750,000 eggs per quintal, that will give us a total of 5,250,000,000 of locusts destroyed in the egg, which otherwise would have very soon renewed the ravages of which the country had so lately been the victim. In 1822 were spent again, in Provence, 2,227 francs for the same object. In 1825 were spent 6,200 francs. A reward of 50 centimes was given for every kilogramme of eggs, and half the sum for every kilogramme of insects. The eggs collected were burnt, or else crushed under heavy rollers. The gathering was entrusted to women and children. The operation consisted in dragging along the ground great sheets, the corners of which were held up. The locusts came and settled on these, and were caught by rolling the sheet up.
In the territory of Saintes-Maries, situated not far from Aigues-Mortes, on the Mediterranean coast, 1,518 wheat sacks were filled with dead locusts, amounting in weight to 68,861 kilogrammes; and at Aries 165 sacks, or 6,600 kilogrammes. The rewards given amounted to 5,542 francs; but, notwithstanding all this, the following year the locusts caused still greater damage.
Locusts are always to be found in Algeria, in the provinces of Oran, Bona, Algiers, and Bougia, but they never commit those terrible ravages which change cultivated countries into deserts. There are in Algeria years of locusts as there are with us years of cockroaches, of blight, of caterpillars, &c. These plagues are fortunately rare. The most terrible took place in 1845 and in 1866. In the former year a formidable invasion of locusts took place. It lasted five months, from March to July, each day bringing new bands of these devastating insects; and M. Henry Berthoud, then in Algeria, saw a column of them, whose passage began before daylight, and had scarcely ended at four o'clock in the afternoon. Dr. Guyon, doctor to the army, and correspondent of the Institute, addressed to this learned body an account of a few peculiarities of this invasion, of which he was a witness. He speaks of a band which passed on the 16th of March over the plain of Sebdon, going in the direction of the desert of Angard. Their passage lasted three hours. The locusts, having found nothing to devour in the desert, came back again, and next day made a descent upon the plain of Sebdon, which is 30 kilomètres long, by 12 to 15 kilomètres broad. In four hours all the crops were devoured, and all vegetation destroyed. "The locusts," says the Doctor, "left behind them an infectious odour of putrid herbs, produced by their excretions."
At Algiers, in the Faubourg Bab-Azoum, they penetrated in masses into the barley stores, and there was the greatest difficulty in driving them away, great barricades being raised before the storerooms to stop the invasion. In 1845 they penetrated into the pits in which the natives preserve their wheat. According to the report of the Commandant de la Place of Philippeville, M. Levaillant, a column of locusts alighted in the country round about that town on the 18th of March, 1845, which extended from 30 to 40 centimètres, and the locusts were found heaped upon the ground to the height of three décimètres.
In the environs of Algiers alone were destroyed, in 1845, 369 quintals of locusts. It is computed that 400 locusts go to a kilogramme. This gives, then, a total of 14,760,000 insects destroyed. As in this number half were probably females, and as each female lays on an average seventy eggs, the result we arrive at is, that this stopped the production of 516,600,000 larvæ on the territory of Algiers alone. The invasion of locusts which took place in 1866 was as disastrous as that of 1845. It was in the month of April, 1866, that the vanguard of these destructive insects appeared. Debouching through the mountain gorges and through the valleys, into the fertile plains near the coast, they alighted first on the plain of Mitidja and on the Sahel of Algiers. Their mass, at certain points, intercepted the light of the sun, and resembled those whirlwinds of snow which, during the storms of winter, hide the nearest objects from our view. Very soon the cabbages, the oats, the barley, the late wheat, and the market-gardeners' plants, were partly destroyed. In some places the locusts penetrated into the interiors of the houses. By order of the government of Algiers the troops joined the colonists in combating the plague; and the Arabs, when they found that their interests were suffering, rose to lend their aid against the common enemy. Immense quantities of locusts were destroyed in a few days; but what could human efforts do against these winged multitudes, who escape into space, and only abandon one field to alight in the next?
It was impossible to prevent the fecundation of these insects. The eggs quickly producing innumerable larvæ, the first swarms were very soon not only replaced, but multiplied a hundredfold by a new generation. The young locusts are particularly formidable on account of their voracity. These hungry masses threw themselves upon everything which was left by those which went before them. They choked up the springs, the canals, and the brooks; and it was not without a great deal of trouble that the waters were cleared of these causes of infection. Almost at the same time the provinces of Oran and of Constantine were invaded. At Tlemcen, where within the memory of man locusts had never appeared, the ground was covered with them. At Sidi-bel-Abbes, at Sidi-Brahim, at Mostaganem, they attacked the tobacco, the vines, the fig-tree, and even the olive-trees, in spite of the bitterness of their foliage. At Relizane and at L'Habra they attacked the cotton-fields. The road, 80 kilomètres long, which connects Mostaganem with Mascara, was covered to the whole of its extent.