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THE HOUSE FLY.
During the latter end of this and the commencement of the following month flies abound, and are frequently a great annoyance in our houses. In such cases our readers will not be unwilling to hear of a simple mode of ridding their rooms of such a nuisance. We quote again from the author of "The Chronicles of the Seasons."
Persons who have never visited the south of Europe during the hot months are doubtless unable to form anything like a correct idea of the annoyance occasioned by flies; but the accounts of travellers who have themselves experienced it are sufficient to show that they are a much more formidable pest in those countries than with us. "It is not," says Arthur Young, "that they bite, sting, or hurt, but they buzz, teaze, and worry; your mouth, ears, and nose, are full of them; they swarm on every eatable; and if they are not incessantly driven away by a person who has nothing else to do, to eat a meal is impossible."
Nor is it only to Spain, Italy, and the other warm regions of Europe, that this nuisance is confined: it seems equally prevalent in the other hot countries of the world; while in the more temperate climes we find the same evil, only in a mitigated form. During the latter part of our summer, the numbers of these insects that enter our apartments, and the active curiosity they display in perching on and running over every object in it, and also the personal annoyances we suffer from them, are sufficiently known. The remedies invented to lessen the inconvenience are almost entirely useless, seeing that if we destroy a large number of these insects by sweetened infusions of green tea, quassia, &c., a number equally large is generally ready to take the place of the destroyed.
It was therefore on a subject of general interest that Mr. Spence wrote, when he communicated to the Entomological Society the account of a mode employed by a friend of his in Florence to remove this drawback to the comfort of existence. He tells us that his curiosity was greatly excited on being told by a gentleman residing in the neighbourhood of that city, that for two or three years he had entirely succeeded in excluding flies from his apartments, though
allowing the windows to be open wide for the admission of air. While the sitting and dining-rooms of his neighbours swarmed with them, a strict search was necessary to detect even two or three in his apartments.
The possibility of excluding flies from a room where the windows were wide open was explained by the curious fact, that flies will not pass through the meshes of a net, even though those meshes are more than an inch in diameter. The plan of this gentleman was simply to suspend a net made of light-coloured thread to the outside of the window, and although every mesh was large enough, not only to admit one fly but several flies with expanded wings to pass through at the same moment, yet from some inexplicable dread of venturing across the mesh-work, these insects were effectually excluded. The gentleman who thus exhibited the merits of the plan to Mr. Spence did not pretend to have been the inventor of it. He said that he first heard of it at a monastery near Florence, and afterwards from an artist at Rome, who warmly expatiated on the important advantage it conferred in allowing him to work in his studio with open windows, and yet be free from the personal annoyance of flies, and the equally great one of their settling on the newlypainted picture.
It is necessary to state, that in order for this plan to succeed, it is essential that the light enter the room on one side only, for if there be an opposite or side-window, the flies pass through the net without scruple. The fact of these insects being excluded by the simple means above stated (when the room is lighted from one side only) has been repeatedly noticed, and fully confirmed.
THE HOUSE FLY.
Nor are we dependent only on accounts of this fact, as received from a foreign country; it has been noticed and confirmed also by observers in England. Dr. Stanley gives an account, in the "Transactions of the Entomological Society," of some experiments entered on by him, in order to the satisfactory investigation of this singular discovery. Nets of various coloured worsted were prepared, the size of the meshes varying from three quarters to one inch on the side of the square. These were stretched over the two windows of a room much exposed to the troublesome intrusion of flies, particularly the blue-bottle (Musca vomitoria), attracted to
the spot by a trellis covered with the sweet-scented clematis, honeysuckles, and other flowering plants. So great was the annoyance occasioned by these insects, that the sashes were often kept closed, even on the hottest days, in order to exclude them. But no sooner were the nets set up, than all inconvenience was at an end.
"I could perceive and hear them," says Dr. Stanley, "hovering on the other side of my barriers; but though they now and then settled on the meshes, I do not recollect a single instance of one venturing across the boundary.
"When one of the nets was withdrawn, or a door was opened communicating with another room, several flies immediately entered, and in attempting to drive them out through the netted window, it was observed that they flew with violence towards the upper pane, avoiding the net-work below.
"A net was now prepared of very fine pack-thread, with enlarged meshes of an inch and a quarter to the square, and this was found to answer the purpose as effectually as the
smaller worked coloured worsteds.
"So fine and comparatively invisible was the pack-thread net, that there was no apparent diminution of either light or the distant view, and for the remainder of the summer and autumn I was enabled to enjoy the fresh air with open windows without the fear of the annoyance I had heretofore experienced. I should also add that, though wasps occasionally came through, the number was very much diminished."
It is very remarkable that an allusion to this fact appears to be made in the writings of Herodotus. After giving a general description of the customs, manners, and religion of the Egyptians, he speaks of the natural history of the country, and a passage occurs of which the following is Mr. Spence's translation:
"But against the gnats, being in great numbers, these are the means they have invented: the towers are of service to those who inhabit the upper parts of the marshes, and ascending into them they sleep there, for the gnats, on account of the winds, are unable to fly high. But those who live around the marshes have invented other means instead of towers. Every man of them possesses a casting-net with
which during the day he catches fishes, and at night he makes use of it in the bed where he reposes, round which he places the net, and then having crept under it he sleeps. But the gnats, if he sleeps wrapped up in a woollen or linen garment, bite through these, but through the net they do not even attempt to bite."
In the "Chronicle of the Seasons," we find the following account, which will not be out of place this month.
The cockchafer is one of the farmer's enemies, and its devastations are often extensive, being carried on both while the insect is in the larva state, and also when it assumes the perfect form. This well-known insect is about an inch in length, the body oblong and convex; the horny wingcovers are of a brown colour, while the back of the head, and the under parts of the body are quite black. The female digs into the soil to some depth, in order to secure a safe place for her eggs. These are very numerous, and are laid in a cluster at the bottom of the hole, which is sometimes six inches deep. The larvæ which are produced from these eggs are dirty-looking grubs, of a yellowish white colour, and apparently quite blind. When full grown they are about an inch and a half in length, the head scaly, and of a light brown colour, the body soft and whitish. These large and somewhat disgusting grubs are often turned up with the soil, and must be well known to most cultivators. The head is furnished with powerful mandibles, and two antennæ, each having five joints. Six short scaly legs on the fore part of the body are the only instruments of motion, while the hinder part remains curved or partially rolled up. The size of these larvæ makes them a rich prize to the rook, and good service is rendered by the industrious bird in lessening their numbers.
During three years does the grub, which we have just described, continue its subterraneous existence, unless
disturbed and destroyed by some of its enemies. The summers of this period are occupied in attacks on the roots, chiefly of the grasses, but sometimes of shrubs and trees; during the winter it descends deeper into the earth, and remains wholly inactive, without requiring food. As the spring approaches it rises to within a few inches of the surface, and prepares to renew its attacks on the different roots. During the third autumn, the larva descends to a greater depth than before, sometimes as much as five or six feet, and forms a case or cocoon in which to undergo its changes. It then assumes the chrysalis state, and in the following spring passes through its final change, and becomes a perfect insect. The beetle is at first soft and light coloured, but it gradually gains consistency, and by the month of May or June it is prepared to leave its subterraneous dwelling, and become an inhabitant of this upper world. Working its way to the surface by means of the head and forelegs, it spreads its wings, and disdaining any longer to grovel in the dust, takes its glad flight to the foliage of the nearest trees, among which it is to spend the brief season of its existence as a perfect insect. The males scarcely exist more than a week, but the life of the female is prolonged for the purpose of laying her eggs. The whole duration of the brood of cockchafers in the winged state may be estimated at one month.
As the place chosen by the parent insect for the deposition of her eggs is generally some rich grass land in the neighbourhood of oak plantations, so we often find the cockchafer abounding on such trees, or among the old ancestral groups that stud the parks of country dwellings. The mischief done to trees by these insects is in general trifling, but there have been cases where it proved far otherwise. Thus, although the ravages of the grub are most to be apprehended during the long period of its working underground, yet we have instances of great devastation committed by the parent insect. One of the most remarkable is that recorded by Dr. Thomas Molyneux, in the 19th volume of the Philosophical Transactions. The writer states that his narrative is not from common hearsay, but is given on "sure ground." This remark is necessary; since we are happily so unacquainted with the plague of