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THE Linnean order Diptera, comprises those insects that have only two wings, each furnished at its base with a poise or balancer.
OF THE OESTRI, OR GAD-FLIES.
From the posterior part of the body of the Gad-fies issues a wimble of wonderful structure. It is a scaly cylinder, composed of four tubes, which draw out like the pieces of a spying-glass. The last of these is armed with three hooks, and is the gimlet with which the insect bores through the tough bide of horned cattle, for the purpose of depositing there her egg. When this is hatched, the grub feeds on the matter issuing from the wound; and the nidus forms upon the body of cattle a lump, sometimes above an inch high. Some of the species deposit their eggs in the nostrils of sheep, and others in places from which the larvæ, as soon as hatched, can be conveyed into the intestines of horses.
The larvæ are without feet, short, thick, soft, and annulate. When full grown, they let themselves fall to the earth, and they generally pass their chrysalid state under cover of the first stone they meet with.
In their general form, the Tipulæ have a general resemblance to the Gnats, but they are easily distinguished from those insects, by having expanded wings, and being destitute of the long proboscis which is so conspicuous in the Gnats. From the commencement of spring until the beginning of autumn, the larger kinds of Tipulæ are to be seen in great numbers in pastures and meadows. Some of the species lay their eggs upon the ground amongst the grass, and others in the hol. lows of decayed trees. The larro are without feet, soft, and cylindrical.
Both the larvæ and chrysalids of the smaller Tipulæ are found in water, and are very various, both in size and color. Some are fur. nished with a pair of arms; and others are enclosed in cylindrical tubes, open at the ends. The latter swim nimbly, but the former always remain in holes which they have formed in the banks of rivu. lets. Some of the species spin a silken case round part of their body. Their whole frame is, in general, so very tender, that, in some of the species, a touch only is sufficient to crush them.
OF THE FLIES IN GENERAL.
The mouth of these insects has a soft, fleshy proboscis, with two equal lips; and the sucker is furnished with bristles. The antennæ are generally very short.
The appellation of Fly has been given almost exclusively to these insects, probably from their being much more common than any others. The larvae of some of the species live in water; those of others are found on trees, where they devour aphides or plant-lice; and others in putrid flesh, cheese, &c. Most of the flies are torpid during the winter, and therefore lay up no provision for their nourishment in the cold season. At the decline of the year, when the mornings and evenings become chilly, many of them come for warmth into houses, and swarm in the windows. At first they appear very brisk and alert; but as they become torpid they seem to move with difficulty, and at last are scarcely able to lift their legs. These seem as if they were glued to the glass; and by degrees many of the insects do actually stick on the glass till they die. It has been observed that some of the flies, besides sharp, hooked nails, have skinny palms or flaps to their feet, by which they adhere to glass and other smooth bodies, and walk on ceilings with their backs downward. They are enabled to do this, by the pressure upon those flaps by the atmosphere; the weight of which they easily overcome in warm weather, when they are brisk and alert. But towards the end of the year this resistance becomes too mighty for their diminished strength; and we see flies laboring along, and lugging their feet on windows as if they stuck fast to the glass; and it is with the utmost difficulty they can draw one foot after another, and disengage their hollow caps from the slippery surface. On a principle exactly similar to this it is, that boys, by way of amusement, carry heavy weights, by only a piece of wet leather at the end of a string, clapped close to the surface of a stone.
It is a very extraordinary fact, that flies have been known to remain immersed in strong liquors, even for several months, and afterwards, on being taken out, and exposed to the air, have again revived. Some, we are told by Dr. Franklin, were drowned in Madeira wine, when bottled in Virginia to be sent to England. At the opening of a bottle of this wine at a friend's house in London, many months afterwards, three drowned Aies fell into the first glass that was filled. The Doctor says, that having heard it remarked that drowned flies were capable of being revived by the rays of the sun, he proposed making the experiment. They were therefore exposed to the sun, upon the seive which had been employed to strain them from the wine. In less than three hours two of them, by degrees, began to exhibit signs of life. Some co:vulsive motions were first observed in the thighs; and at length they raised themselves upon their legs, wiped their eyes with their fore-feet, and, soon afterwards, flew away. The Rev. Mr. Kirby informs me, that he has made the same observation on flies
THE COMMON-FLESH FLY-HESSIAN FLY-CHEESE-FLY. 979
taken out of home-made wines. He says that many have recovered, after having been twelve months immersed.
THE COMMON FLESH-FLY.
It is a fact not generally known, that this is a viviparous insect, depositing its offspring, in a living state, on the meat in our shambles and larders. The young.ones appear under the same worm-like form, as the grubs produced from the Blue Flesb-fly. They feed as those do, increase in size, undergo all their transformations in the same manner, and even in the fly-state appear but little different.
THE HESSIAN FLY.
Among the various causes of alarm experienced by the farmer in the course of his rural labors, few are more powerful, though many more justly so, than the larvæ or grubs of this little fly. These are lodged and nourished within the stems of wheat and rye, just above the
root, which they entirely destroy.
The larvæ of these flies are the troublesome maggots found in cheese, and so well known to housewives under the name of Hoppers. They proceed from eggs deposited in the crevices or holes of the cheese by the parent fly:
This maggot is surprisingly strong and vigorous, and, when disturbed leaps to a considerable distance. To do this, it erects itself on its tail, and, bending its head into a circle, fixes two black claws, which are situated at the end of the tail into two cavities formed for their
reception at the back of the head. It then exerts its muscular powers, and, in suddenly extending its body, throws itself, for its size, to a vast distance. One of these insects, which was not the fourth of an inch long, has been known to leap thus, out of a box six inches deep, or to twenty-four times its own length.
OF THE TABANUS, OR WHAME-FLY TRIBE.
The insects of the present tribe subsist on the blood of animals, which they suck with great avidity, by means of their proboscis. They are chiefly active during the hottest weather of summer. In most of the species the eyes are beautifully colored. Wet meadows and moist woods are the places in which they principally abound The larice of some of the species live underground.
THE HORSE-FLY, AND GREEN-EYED WHAME-FLY.
THE HORSE-FLY, AND GREEN-EYED WHAME-FLY,
The puncture of both these insects is extremely keen and painfui. During the summer-time, the former torment horses and cattle in such a degree, as sometimes to throw them into a state of the utmost agitation and alarm. They are more abundant in wet meadows and pastures than in other places.. Mankind are also not unfrequently attacked by them.
The Green-eyed species often torment mankind. who are accustomed to walk in shady lanes, and in woods, during the hot weather of June and July, know well what it is to suffer from their attacks.
OF THE GNATS.
THESE insects principally frequent woods and watery places, and, in many parts, are known to the country people by the name of Midges. They live by sucking the blood and juices of the larger animals.
Their larvae are very common in stagnant waters. The bodies of these are composed of nine segments, the last of which is furnished with a small cylindrical tube, through which they breathe; and they frequently rise to the surface of the water for that purpose. The head of the chrysalis is bent towards the breast, so as to throw the thorax in front: in this the respiratory tubes are situated, near the head. The last segment of the abdomen terminates in a kind of flat fin, by means of which the creature performs all its motions in the water.
THE COMMON GNAT.
Few insects are better known than this species of Gnat; and there are not many that afford a more interesting history.
The female deposits her eggs on the surface of the water, and sur: rounds them with a kind of unctious matter, which prevents them from sinking; and she at the same time fastens them with a thread to the bottom, to prevent them from being floated away from a place, the warmth of which is proper for their production, to any other where the water may be too cold, or the animals their enemies, too numerous. In this state, therefore, they resemble a buoy that is fixed by an-anchor. As they come to maturity they sink deeper; and at last, when they leave the egg, they creep, in the form of grubs, at the bottom.
It is impossible to behold' and not admire the beautiful structure of the probo:cis, through which the Gnat draws the juices that afford it
THE MUSQUITO-FLY-THE SPIDER FLIES.
nourishment. The naked eye is only able to discover a long and slender tube, containing five or six spiculæ of exquisite fineness. These spiculæ, introduced into the veins of animals, act like the suckers of a pump, and cause the blood to ascend. The insect injects a small quantity of liquid into the wound, by which the blood is made more fluid. The Gnat, as it sucks, swells, grows red, and does not quit its hold till it has gorged itself.'. The liquor it has injected causes a disagreeable itching, which may in some degree be removed by volatile alkali, oi by immediately rubbing, and washing the place with cold water.
The Musquito-fly is nothing more than a large variety of the Com. mon Gnat. These insects are found in great abundance in the woody and marshy parts of all hot climates; and, during the short buinmer, throughout Lapland, Norway, and Finland, and other countries equally near the Pole.
It is the female only that bites and sucks the blood; and tliis operation is so severe, as to swell and blister the skin in a violent manner and sometimes even to leave obstinate sores.
The lowest class of people, in all the climates where Musquitoes abound, keep them out of their huts, during the day-time, by burning there a continual fire: the Laplander, when in bed, has a better con, trivance to defend himself from their stings. He fixes a leather thong, to the poles of his tent, this raises his canvass quilt to a proper height, 80, that its sides or edges touch the ground, Under this he creeps and, passes the night in security. When Mr. Acerbi and his friends arrived in a cottage in the village of Killare, in Lapland, the first favor the women conferred on them, was to light a fire, and fill the room so full of smoke, that it brought tears from their eyes. This was done to deliver them from the molestation of the Musquitoes; and, as a means of effectual prevention, they made a second fire, near the entrance of the apartment, to stop the fresh myriads, which would otherwise have rushed in upon them from without. The buzzing of Musquitoes is so loud, as to disturb the rest of persons in the night, almost as much as would be done by their bite.
OF THE HIPPOBOSCÆ, OR SPIDER-FLIES.
THE Hippoboscæ form a connecting link between the two-winged and the apterous insects. By some authors they have been denominated mouches araignées, or spider-flies, from a distant resemblance which some of them have to Spiders.
A few of the species are found in woods and marshy places; but the greater number of them infest the bodies either of quadrupeds or