Part 22
The caterpillars live and metamorphose themselves in portable cases, which they manufacture from the membranous portions of leaves, whose flesh alone they eat. These cases are generally of a brown colour, resembling a dead leaf. They are attached perpendicularly under the leaves of many trees, but often under those of fruit trees.
Certain species of _OEcophoræ_ have cases partly covered with loose pieces only slightly attached, formed of portions of leaves, and arranged in such a way that Réaumur compares them to the furbelows which ladies used formerly to attach to the bottom of their dresses.
V.
ORTHOPTERA.
Among the Orthoptera[76] we meet with some of the largest of insects, and particularly those which are of strange and extraordinary shapes. The best known insects of this order are the _Mantes_, Cockroaches, Earwigs,[77] Locusts, Grasshoppers, Crickets, &c.
[76] From [Greek: orthos], straight, and [Greek: pteron], wing, on account of the manner in which the under-wings are folded under the upper.--ED.
[77] Made a separate Order, _Dermaptera_, by Kirby.--ED.
The Orthoptera have the anterior wings long, narrow, half-horny. These are elytra, which serve as cases for their second wings, as is the case with the Coleoptera. But the elytra of the Orthoptera are less solid and less complete than those of the Coleoptera. Moreover, they generally overlap each other when the insect is at rest, which is another distinctive characteristic. The second wings are membranous, very broad, and veined; and, when at rest, are folded up like a fan. The mouth is composed of free pieces. The mandibles, the jaws, and the two lips, always well developed, show them to be insects which grind their food. Their voracity, and the rapid way in which they multiply, sometimes make these insects the pest of the country. Above all, they are to be met with in hot countries, where they cause such great damage that all vegetation disappears on their passage. There are not a great variety of species of Orthoptera. They are insects whose metamorphoses are incomplete; that is, they undergo only trifling changes from the moment when the eggs are hatched to the time when the insect is fully developed.
When it leaves the egg, the young one resembles its parents; it differs only in size and in having no wings. After moulting four or five times it has almost reached its full growth, and its wings begin to appear under a sort of membrane. This is the pupa state. A final moulting sets free the wings also, and the insect, now perfect, launches itself into the air with its congeners.
The Orthoptera are vegetable feeders, and frequently commit great ravages on various crops. They are divided into two groups, viz., those which _run_, and those which _jump_ or _leap_. We will begin with those which run, which contains the Earwig (_Forficula_), the Cockroach (_Blatta_), the genus _Mantis_, or Leaf Insects, and the genus _Phasma_.
The _Forficula_, or Earwig, is represented in Figs. 298, 299, 300, in its three different states. The lower wings are very broad, and folded at the same time like a fan, and doubled up. Its abdomen terminates in a sort of pair of pincers, resembling those which the jewellers formerly used for piercing the ears of young girls as a preparatory step to their wearing ear-rings. Hence, without doubt, their French name of _Perce-oreille_, or ear-piercer; for there is nothing to justify the vulgar belief that these insects introduce themselves into the ear, and bore a hole into its interior, through which they may penetrate into the brain; in fact, they are very innocent insects, and do little harm. They live on vegetable matter, and more especially the interiors of certain flowers.
The _Forficulæ_ avoid the light. They are to be found in the chinks of trees, under bark, and under stones. The female watches over the eggs with maternal solicitude, and carries them away elsewhere when they are touched. She also protects the larvæ and pupæ till they are strong enough to dispense with all attention.
The _Blattæ_, or Cockroaches, are very destructive insects, as the name, derived from the Greek word [Greek: Blaptein], to damage, implies. They are omnivorous, attacking all sorts of dead substances, vegetable and animal. Horace reproaches them with devouring stuffs, like the moths:--
"Cui stragula vestis, Blattarum ac tinearum epulæ, Putrescit in arca."
These disagreeable insects devour our eatables, abounding in kitchens, in bakers' shops, on board merchant vessels, &c. Their flattened bodies allow them easily to introduce themselves into the cracks of cases or barrels; so that, to be safe against their attacks, it is necessary, on long voyages, to shut up the goods in zinc-lined boxes, or cases made of sheet-iron well soldered together.
Chamisso relates that the sailors having opened some barrels which should have contained rice and wheat, found them filled with German Cockroaches (_Blatta Germanica_). This transubstantiation was not very agreeable to the crew! Other naturalists have seen this insect invading by millions bottles which had contained oil. The Cockroach is very fond also of the blacking on boots, and devours leather and all. One pupa sometimes eats the skin cast off by another pupa, but a Cockroach has never been known to attack another with a view to eating him afterwards.
These Orthoptera have a flat broad body, the thorax very much developed, the antennæ very long, and the legs thin but strong, which enable them to run with remarkable quickness. They diffuse around them a sickening odour, which often hangs about objects they have touched. Aristophanes, the Greek comic poet, mentions this peculiarity in his comedy of "The Peace." They come out mostly at night, and hide themselves during the day. They are the most cosmopolitan of all insects. Carried over in ships, they perpetuate everywhere, just like weeds! Persian powder, composed of pulverised _pyrethra_, is an excellent means to employ for their destruction.
Most of the species of cockroaches are black or brownish. Two among them, the _Blatta Germanica_ and the _Blatta Laponica_, which are to be met with in the woods round about Paris, have domesticated themselves in dwellings of the northern countries. They are a quarter of an inch in length. The Russians pretend that the former was imported from Prussia by their army, on its return from Germany, after the Seven Years' War (1756-1762). Till this period it was unknown at St. Petersburg, where now-a-days it is met with in great numbers. It lives in houses, and eats pretty nearly everything, but prefers white bread to flour and meat. The _Blatta Laponica_ devours the smoked fish prepared for the winter.
The German naturalist, Hummel, made some interesting observations on the development and habits of the very prolific _Blatta Germanica_. It lays its eggs in a silky capsule, which is in the form of a bean, with two valves in the interior. This is drawn about for some time appended to the extremity of the abdomen, and after a time abandoned.
Hummel placed under a bell-glass a female cockroach and a perfect egg-pouch, which had only just been abandoned by another female. He saw the cockroach approach the bag, feel it, and turn it about in all directions. She then took it between her front legs, and made a longitudinal opening in it. As the opening grew wider, little white larvæ were seen to come from it rolled up and attached together. The female presided at this operation. She assisted the larvæ to set themselves free, aiding them out gently with her antennæ. In a few seconds they were able to walk, when she ceased to trouble herself about them.
The larvæ change their skin six times before reaching the perfect state. When they come out of their skin they are colourless, but the colour comes in a few minutes. At the fifth moult, which takes place three months after birth, they become pupæ, with rudimentary wings, the whole shape of the insect being well marked. The sixth, or last moult, takes place at the end of six weeks. The pupa is now changed into a perfect insect. The female is distinguished from the male by the greater size of her abdomen.
The most destructive of the _Blattæ_, or Cockroaches, are those which have been imported into Europe by the ships coming from the colonies. The _Kakerlac Americana_ is from an inch to an inch and a quarter long. It infests ships, running about at night over the sleeping passengers, and devouring the food. They are to be met with in all parts of the world. They abound particularly in the warm parts of America. The _Blatta orientalis_ is more commonly met with than the above. It swarms in kitchens, in bakers' shops, provision shops, &c., where it hides in the cracks of the walls, or against the hinges of the doors. It is a small hideous animal, of a repulsive smell, and of a reddish brown colour. It is a little larger than the _Blatta Americana_. In France it is called by various names, such as _Cafard_, _Panetière_, _Noirot_, _Bête noir_, &c. If in the middle of the night you suddenly enter with a light into the down-stairs kitchens, you will often see these little beasts running about on the table, and devouring the remains of the food with astonishing rapidity.
The largest species of the genus of which we are now treating is the _Kakerlac insignis_, which inhabits Cayenne and Brazil, and in length sometimes exceeds an inch and three-quarters, and in the extent of its wings four inches and a half.
It is principally in hot countries that the cockroaches do the greatest damage. In the Antilles, of which they are the pest, it is affirmed that in one single night they can bore holes through trunks, through cases, and through bags, and destroy objects which were supposed to be in perfect safety. Sometimes the walls, the floors, the beds, the tables, everything, in short, is infested by them, and it is impossible to find a way of preserving the food from their repulsive touch. One can, however, partially succeed in destroying them by the aid of insect powders. They have, however, natural enemies. Poultry and owls are very fond of them. A species of wasp, _Chlorion compressum_, lays up a stock of cockroaches, which it previously renders insensible, for its larvæ. Many species of _Chalcidiæ_, a family of Hymenoptera, also live on the eggs of these Orthoptera. There are also among the cockroaches certain brightly-coloured exotic species. These colours show that they do not avoid the light. We will mention as examples the _Brachycola robusta_ and the species of _Corydia_.
The _Mantidæ_ are pretty insects, of very different habits from the preceding. They alone of the Orthoptera are carnivorous. They eat live insects, seizing their prey as it passes by them. They rest generally on shrubs, remaining for hours together perfectly motionless, the better to deceive other insects which are to become their victims.
It is this fixed and as it were meditative attitude which has gained for them the name of _Mantis_, derived from the Greek word [Greek: mantis], or "diviner," as it was imagined that in this attitude they interrogated the future. The manner in which they hold their long front legs, raised like arms to Heaven, has also contributed to make this superstitious notion believed, and sufficiently explains the names given to divers species of _Mantidæ_; such as Nun, Saint, Preacher, Suppliant, Mendicant, &c. Caillaud, a traveller, tells us that in Central Africa a _Mantis_ is an object of worship. According to Sparmann, another species is worshipped by the Hottentots. If by chance a _Mantis_ should settle on a person, this person is considered by them to have received a particular favour from heaven, and from that moment takes rank among the saints!
In France the country people believe that these insects point out the way to travellers. Mouffet, a naturalist of the seventeenth century, says on this subject, in a description of the _Mantis_:--"This little creature is considered of so divine a nature, that to a child who asks it its way, it points it out by stretching out one of its legs, and rarely or never makes a mistake."
In the eyes of the Languedoc peasants the _Mantis religiosa_ is almost sacred. They call it _Prega-Diou_ (_Prie-Dieu_), and believe firmly that it performs its devotions--its attitude, when it is on the watch for its prey, resembling that of prayer. Settled on the ground, it raises its head and thorax, clasps together the joints of its front legs, and remains thus motionless for hours together. But only let an imprudent fly come within reach of our devotee, and you will see it stealthily approach it, like a cat who is watching a mouse, and with so much precaution that you can scarcely see that it is moving. Then, all of a sudden, as quick as lightning, it seizes its victim between its legs, provided with sharp spines, which cross each other, conveys it to its mouth, and devours it. Our make-believe Nun, Preacher, our _Prega-Diou_, is nothing better than a patient watcher and pitiless destroyer. The _Mantis religiosa_ (Fig. 302), common enough in the south of France, comes as far north as the environs of Fontainebleau. The _Mantis oratoria_, rather smaller, is less commonly met with.
These elegant insects are remarkable for their long slim bodies, their large wings, and their colours, which are generally very bright. In some species their green or yellowish elytra look so exactly like the leaves of trees that one can hardly help taking them for such.
The _Mantis_ lays its eggs at the end of summer, in rounded, very fragile shells, attached to the branches of trees; they do not hatch till the following summer. The larvæ undergo several successive moultings. Nothing equals the ferocity of these Orthoptera. If two of them are shut up together, they engage in a desperate combat; they deal each other blows with their front legs, and do not leave off fencing until the stronger of the two has succeeded in eating off the other's head. From their very birth, the larvæ attack each other. The male being smaller than the female, is often its victim.
Kirby tells us that in China the children procure them as in France they do cockchafers, and shut them up in bamboo cages, to enjoy the exciting spectacle of their combats.
_Acanthops_, a genus of this family, inhabits the Brazils.
Akin to the _Mantis_ are the _Eremiaphilæ_, which live in the deserts of Africa and Arabia. They drag themselves gently along on the ground, and as they are the same colour as the sand on which they are found, it is very difficult to distinguish them when at rest. The traveller, Lefebvre, relates that he always found these Orthoptera in places destitute of all vegetation, and where there were no other sorts of insects which could have served them for food; it is therefore probable that they live on microscopic insects.
The _Empusa_, which forms another genus of _Mantidæ_, has the antennæ indented like a comb in the males, thread-like in the females. The _Empusa gongylodes_, which inhabits Africa, has cuffs to its arms and flounces to its robe.
The genus _Blepharis_, to which belongs the _Blepharis mendica_, is met with in Egypt, Arabia, and in the Canary Islands. This insect, which is of a pale green, is not rare in the south of France. It is represented with the _Mantis religiosa_ in Fig. 302.
The _Phasmata_, or Spectres, are distinguished from the _Mantidæ_ by their very elongated bodies, straight and stiff as a stick, by their having no prehensile legs, and by their food, which is exclusively vegetable. Their eggs are laid uncovered, having no silky envelope. As for the habits of these insects, they are little known, the greatest number of the species being exotics, inhabiting chiefly South America, Asia, Africa, and New Holland. It is in this tribe that we meet the most extraordinary and the most monstrously shaped insects, as the popular names they have received in different countries show: such as Spectres, Phantoms, Devil's Horses, Soldiers of Cayenne, Walking Leaves, Animated Sticks, &c.
Among the Phasmæ we also find the largest insects known, for they attain a considerable length, _Phasma gigas_ nearly reaching a foot. The most beautiful are those of New Holland and of Tasmania, such as _Cyphocrana (Phasma) gigas_.
Some species are destitute of wings, and resemble so exactly dry sticks that it is impossible to tell the difference. The best known is the _Bacillus (Phasma) Rossia_ (Fig. 303), which is found in the south of France. This inoffensive insect walks gently along the branches of trees, and likes to repose in the sun, its long antennæ-like legs stretched out in front. Others of the genus _Phyllium_ are provided with wings, and have altogether the appearance of the leaves on which they live; such are the Walking Leaves of the East Indies. According to Cunningham, all these insects are of solitary and peaceable habits. They are only to be met with alone or in pairs, drawing themselves gently along on shrubs, on which they pass the hottest months of the year. Some of them, when they are seized, emit a milky liquid of a very strong and disagreeable odour.
Those Orthoptera which we have already mentioned had all their six legs adapted to running, and are called _Cursoria_. Those which jump, to which we now come, have their hind-legs stronger and thicker, which enables them to leap, and are on that account called _Saltatoria_. This section comprises three families, which have for their principal types the Crickets, Locusts, and Grasshoppers.
All these insects resemble each other in the disproportion which exists between their hind-legs and the other pairs. Another characteristic which is common to them consists in the song of the males. This song, so well known, which seems to have for its object to call the females, is nothing but a sort of stridulation or screeching, produced by the rubbing together of the wing cases, or elytra. But the mechanism by which this is produced varies a little in all the three kinds. With the Crickets the whole surface of the wing cases is covered with thick nervures, very prominent and very hard, which cause the noise the insect produces in rubbing the elytra one against the other. With the Locusts, there exists only at the base of the elytra a transparent membrane called the mirror, which is furnished with prominent nervures, and produces the screeching noise. And, lastly, in the Crickets the thighs and elytra are provided with very hard ridges. The thighs, being passed rapidly and with force over the nervures of the elytra, produce the sound, in the same way as a fiddle-bow when drawn across the strings of a violin. In all these insects the male alone is endowed with the faculty of producing sound.
The Crickets and Grasshoppers have very long and thin antennæ, whilst the Locusts have short antennæ, and either flattened or filiform, or swelling out at one extremity like a club. The female of the first two is provided with an ovipositor in the shape of an auger.
We will study successfully the three types of these families, that is to say, the Crickets, the Locusts, and the Grasshoppers.
The Field Cricket (_Gryllus campestris_, Fig. 304) lives alone in a hole which it digs in the ground, and in which it remains during the day. It only quits its retreat at night, when it goes in search of food. It is very timid, and at the least noise ceases its song. If it is stationed on the side of its hole, it retreats into it the moment any one approaches.
The holes of the crickets are well known to country children, who take these insects by presenting a straw to them. The pugnacious cricket seizes it directly with its mandibles, and lets itself be drawn out of its hole. It is this which has given rise to the saying, "_plus sot qu'un grillon_" (a greater fool than a cricket). It is very susceptible of cold, and always makes the opening of its hole towards the south. It lives on herbs, perhaps also on insects.
The House Cricket is about half an inch long, of an ashy colour, and is to be met with principally in bakers' shops and country kitchens, where it hides itself during the day in the crevices of the walls or at the back of the fireplaces. It eats flour, and also, perhaps, the little insects which live in flour.
If crickets are put into a box together, they devour each other. This does not prove conclusively that they are carnivorous, for there are many species, eating nothing but vegetables, which would destroy each other in a similar case. Some authors say that these insects are always thirsty, for they are often to be found drowned in the vessels containing any kind of liquid. Everything damp is to their taste. It is for this reason that they sometimes make holes in wet clothes, which are hung up before the fire to dry. They inhabit, by preference, houses newly built; for the mortar, being still damp, allows them to hollow out their dwelling-places with greater ease.
The habits of the House Cricket (_Gryllus domesticus_) are nocturnal, like those of its congener of the fields. It is only at night that it leaves its retreat to seek its food. When it is exposed against its will to the light of day, it appears to be in a state of torpor. This insect reminds one of the owl, among birds, not only from its habit of avoiding the light, but also from its monotonous song, which the vulgar consider, one does not know why, a foreboding of ill-luck to the house in which it is heard. Formerly this singular prejudice was much deeper rooted than it is at present The song of the cricket has merely the object of calling the female. The Wood Cricket (_Gryllus_ [_Nemobius_] _sylvestris_) is much smaller than the above, and is met with in great numbers in the woods, where its leaps sometimes produce the noise of drops of rain.
The female crickets have a long egg-layer, or ovipositor, with which they deposit their eggs, of which each one lays, towards the middle of the summer, about three hundred, in the cracks and crevices of the soil. The larvæ pass the winter in that state, and do not become pupæ and perfect insects till the following summer.
Mouffet relates that, in certain regions of Africa, the crickets are objects of commerce. They are brought up in little cages, as we do Canary birds, and sold to the inhabitants, who like to hear their amorous chant. It is said that some tribes eat these insects. In France they are sought after as baits for fishing, and are used also in menageries for feeding small reptiles. Next to _Gryllus_ come the genera _OEcanthus_, insects of the south of Europe, which live on plants, and which one often sees fluttering about flowers; _Sphæria_, which live in ant-hills; _Platydactylus_; and, lastly, the Mole Cricket (_Gryllo-talpa_), whose habits deserve attention for a while.
The Mole Crickets are distinguished from all other insects by the structure of their fore-legs, which are wide and indented, in such a manner as to resemble a hand, analogous to that of the mole. This leg betrays the habits of the cricket much better than our hands betray ours. They make use of them, indeed, as spades, with which they hollow out subterranean galleries, and accumulate at the side of the entrance-hole the rubbish thus drawn out. The French name comes from the old French word _courtille_, which means garden. Such places and vineyards are the favourite haunts of these destructive insects.