In the vertebrated animals, the blood is driven through branching tubes to receptacles of air placed within the chest; the air-channels terminate in blood extremities, and the blood-vessels cover these as a net-work. The mechanical act of respiration merely serves to change the air contained within the air-receptacles. In the insects, this entire process is reversed; the air is carried by branching tubes to receptacles of blood scattered throughout the body; the blood-channels terminate in blood-extremities, and a capillary net-work of air-vessels is spread over these. Now, in the vertebrated creature, the chest is merely the grand air-receptacle into which the blood is sent to be aërated; while in the insect, the chest contains but its own proportional share of the great air-system. In the latter case, therefore, there is a great deal of available space, which would have been, under other circumstances, filled with the respiratory apparatus, but is now left free to be otherwise employed. The thoracic cavity of the insect serves as a stowage for the bulky and powerful muscles that are required to give energy to the legs and wings. The portion of the body that is almost exclusively respiratory in other animals, becomes almost as exclusively motor in insects. It holds in its interior the chief portions of the cords by which the moving levers and membranes are worked, and its outer surface is adorned by those levers and membranes themselves. Both the legs and wings of the insect are attached to the thoracic segment of its body.
The extraordinary powers of flight which insects possess are due to the conjoined influences of the two conditions that have been named—the lightness of their air-filled bodies, and the strength of their chest-packed muscles. Where light air is circulated instead of heavy blood, great vascularity serves only to make existence more ethereal. Plethora probably takes the insect nearer to the skies, instead of dragging it towards the dust. The hawk-moth, with its burly body, may often be seen hovering gracefully, on quivering wings, over some favourite flower, as if it were hung there on cords, while it rifles it of its store of accumulated sweets by means of its long unfolded tongue. The common house-fly makes 600 strokes every second in its ordinary flight, and gets through five feet of space by means of them; but when alarmed, it can increase the velocity of its wing-strokes some five or six fold, and move through thirty-five feet in the second. Kirby believed, that if the house-fly were made equal to the horse in size, and had its muscular power increased in the same proportion, it would be able to traverse the globe with the rapidity of lightning. The dragon-fly often remains on the wing in pursuit of its prey for hours at a stretch, and yet will sometimes baffle the swallow by its speed, although that bird is calculated to be able to move at the rate of a mile in a minute. But the dexterity of this insect is even more surprising than its swiftness, for it is able to do what no bird can: it is able to stop instantaneously in the midst of its most rapid course, and change the direction of its flight, going sideways or backwards, without altering the position of its body.
As a general rule, insect wings that are intended for employment in flight are transparent membranes, with the course of the air-tubes marked out upon them as opaque nervures. These air-tubes, it will be remembered, are lined by spires of dense cartilage; and hence it is that they become nervures so well adapted to act like tent-lines in keeping the expanded membranes stretched. In the dragon-flies, the nervures are minutely netted for the sake of increased strength; in the bees, the nervures are simply parallel. Most insects have two pairs of these transparent membraneous wings; but in such as burrow, one pair is converted into a dense leather-like case, under which the other pair are folded away. In the flies, only one pair of wings can be found at all, the other pair being changed into two little club-shaped bodies, called balancers.
Butterflies and moths are the only insects that fly by means of opaque wings; but in their case the opacity is apparent rather than real, for it is caused by the presence of a very beautiful layer of coloured scales spread evenly over the outer surface of the membranes. When these scales are brushed off, membraneous wings of the ordinary transparent character are disclosed. The scales are attached to the membrane by little stems, like the quill-ends of feathers, and they are arranged in overlapping rows. The variegated colours and patterns of the insects are entirely due to them. If the wings of a butterfly be pressed upon a surface of card-board covered with gum-water to the extent of their own outlines, and be left there until the gum-water is dry, the outer layer of scales may be rubbed off with a handkerchief, and the double membranes and intervening nervures may be picked away piecemeal with a needle's point, and there will remain upon the card a most beautiful representation of the other surface of the wings, its scales being all preserved by the gum in their natural positions. If the outlines of the wings be carefully pencilled first, and the gum-water be then delicately and evenly brushed on, just as far as the outlines, a perfect and durable fac-simile, in all the original variety of colour and marking, is procured, which needs only to have the form of the body sketched in, to make it a very pretty and accurate delineation of the insect.
RUSTICATION IN A FRENCH VILLAGE.
Poverty is difficult to bear under any circumstances, but when compelled entirely to alter our habits of life in the same place where we have lived differently, we certainly feel it more acutely than when we at once change the scene, and see around us nothing we can well compare with what is past. It is unnecessary to say by what means our easy fortune was reduced to a mere pittance; but, alas! it was so, and we found ourselves forced to seek another dwelling-place. Following the example of most of our country-people in a similar situation, therefore, we resolved to go abroad; not, indeed, to enjoy society on an income which would in England totally shut us out from it, but to live in absolute retirement upon next to nothing. A cousin of mine—whose friend, Mlle de Flotte, long resident in England, had married a countryman of her own, and settled in Normandy—wrote to Mme de Terelcourt accordingly, to ask if there was a habitable hut in her neighbourhood where we might find shelter for three years, before which time we were told the settlement of our affairs could scarcely be completed. The answer was favourable: there was, she said, near the village of Flotte, a cottage which contained a kitchen, three rooms, and a garret where a bonne might sleep. A large garden was attached to it full of fruit-trees, though in a most neglected condition, and even the house requiring to be made weather-tight; but as the landlord undertook this latter business, and the rent for the whole was only L.12 a year, we gladly closed with the offer, and at the end of the month of April proceeded to take possession of our new home.
The situation was most lovely. The garden surrounded three sides of the cottage, and a large green field, or rather thinly-planted apple-orchard, the other, where grazed four fine cows belonging to a farm on the opposite side of the lane, which supplied us with butter, eggs, and milk, and was near enough not to annoy but to gratify our ears with the country sounds so pleasant to those fond of rural things, and to give us the feeling of help at hand in case of any emergency. We were on the slope of a tolerably lofty hill; the high-road was below, where we could see and hear the diligence pass; but saving this, the farm-yard noises, and the birds and bees in the garden, were the only disturbers of our perfect quiet, except, indeed, the soothing sound of a small brook tinkling over a tiny waterfall, quite audible, although a good way on the other side of the grande route. The town of C—— was seen to our right, the sea glittering beyond; and a rocky, shrubby dell, through which the little stream above mentioned murmured merrily on its way, turning a rustic mill, was the prospect from the windows. Two lime-trees stood at the gate, inside of which we joyfully discovered an unexpected lodge or cottage, containing two little rooms and a large shed, which had not been mentioned in the description, and which we found most useful for stowing away packing-cases, hampers, and boxes, keeping potatoes and apples, and a hundred things besides. The short road—avenue, our landlord termed it—which led from this to the house, had a strawberry-bank on one side, a row of cherry-trees on the other; and the garden, although overgrown with weeds and sprawling shrubs, looked quite capable of being easily made very pretty indeed. The entrance to this our magnificent château was through the kitchen only; for the room next it, although it could boast of an outside-door likewise, had none which opened into the interior of the house, was neither lathed nor plastered, and the bare earth was all there was to tread upon. Upstairs the flooring consisted merely of planks laid down; and you could hear when below the pins dropped from above, unless, indeed, they fell, as they generally did, into the large crevices. The bonne's mansarde was but a garret, where, till you got into the very middle, you could not stand upright; and although the tiled roof had been just painted and repaired, the breath of heaven came wooingly in every direction, even through the thick-leaved vines which covered it, closely trained up there, to make room for the apricots that grew against the wall below. Close by, a little stair led you out upon a terrace, where a road, bordered by peach-trees and backed by plums, gave a dry walk in all weathers; but you could go higher, higher, and higher still, terrace after terrace, till it terminated in a rock covered with briers and brambles—the fruit of which latter were as large and as good as mulberries. This we called our garden-wall, and it had a sunny seat commanding an extensive view, and from which all we saw was beautiful. How often have I sat there dreaming, lulled by the murmur of the insect world around, till the merry fife of a band of conscripts on their march, or the distant boom of a cannon from the forts, restored me to a consciousness that I was still at least in the world, although not of it.
But now I am going to descend to figures, and can assure my incredulous English readers, that what I relate is strictly true—vraie, although not vraisemblable. We hired a stout girl to weed and wash, without food, at 2½ d. a day; and another for L.5 per annum undertook to be our sole servant—to clean, and cook, and dress madame, only stipulating that she was to have soupe à la graisse and brown bread à discrétion three times a day, two sous for cider, her aprons, and washing; but hoped if she gave satisfaction, that sometimes upon Sunday she might be allowed a bit of meat: on Fridays an egg and an apple contented her, and an occasional fish made her shout with joy. An old soldier, who had returned to his primitive employment of gardener, and lived near, undertook to dig, prune, and plant in the garden for a franc a day, during the time we ourselves were engaged with the inside of our mansion, and to come afterwards at 2d. an hour when we wanted him, either to go to C—— for marketing, or to do anything else we required, for the hamlet of Flotte did not possess many shops. At this hamlet, however, we obtained bread and a variety of small articles on very moderate terms.