Fly (insect)

“ Many of my readers are well acquainted with that fly which in the latter part of summer is seen to be so annoying to the horse, buzzing about him, and every now and then dashing itself with some degree of violence against his sides and legs. This motion, to all appearance, is without design; but a closer study of the habits of the insect will show that, far from being the effect of chance, it is one of paramount importance to the existence of the fly, as on it depends the continuation of its species. ”

“ In particular, the new-born insects of a tribe of flies which produce the aphis-lion larva before spoken [333] of, are distinguished by this peculiarity. We behold a very little insect emerge from the pupa-case, and in a quarter of an hour we are astonished to find it has grown to a great fly! This sudden increase appears the more marvellous, because during this period the insect takes no nourishment. The wings of this insect, when it is just born, are not more than one-tenth the size they acquire in that short space of time. ”

“ Dragon-flies and bees may be cited as examples of insects that often fly for two or three miles. But this is exceptional, and the usual shortness of insect flight is an important fact for man since it limits the range of insects like house-flies and mosquitoes which are vehicles of typhoid fever and malaria respectively. The most primitive insects (spring-tails and bristle-tails) show no trace of wings, while fleas and lice have become secondarily wingless. It is interesting to notice that some insects only fly once in their lifetime, namely, in connection with mating. ”

“ The stricken insect at once drops to the ground. Examination reveals no physical injury to the victim, but on a close inspection there may be found adhering to the under surface of a wing several tiny, soft, white bodies. Poison pills? Pellets of infection? Nothing so ordinary. The things are alive, they creep along the foids of the wing toward its base—they are, in short, young flies born at the instant the body of the mother fly struck the wing of the grasshopper. But a young fly would never be recognized as the offspring of its parent ”

“ The point has been made that even under these conditions it is best to use the dry fly on the ground that, dry or wet, the floating fly is materially, in form and coloration, a better [74] imitation of the natural fly than is the average wet fly. Under like circumstances the natural insect acts in a similar manner, that is, is drawn under the surface in broken water and carried here and there by conflicting currents. ”

“ Though it generally lives in the water, it sometimes, however, crawls out in good weather; and drying its wings by expanding them in the sun, takes flight, and becomes an inhabitant of the air, not to be known as the same creature, unless to those who had accurately observed it before: when tired of flying, or in danger of an enemy, it immediately plunges into the water. We are told that there are fourteen species of it, seven of which are common in Europe, in waters, &c.
Ephemeral Flies.—This species of insect is named ephemeral, because of its very short existence in the fly state. ”

“ At the larger end, under which the head of the fly lies, and from which it always issues, there is commonly a sort of lid which can be pushed off like the lid of a box, and the insect can then walk out at pleasure. But in the case of the pupa of the blow-fly this lid is not very easily removed, and the fly, therefore, is furnished with a most ingenious method of thrusting it off. On opening the larger end of such a pupa, if the fly within is ready to come out, a most curious phenomenon will be seen. ”

“ Bird and fly seem to know each other wonderfully well.
Here, then, we have a parasitical insect specialized in the highest degree, yet retaining all its pristine faculties unimpaired, its love of liberty, and of associating in numbers together for sportive exercises, and well able to take care of itself during its free intervals. And probably when thrown on the world, as when nests are blown down, or the birds get killed, or change their quarters, as they often do, it is able to exist for some time without avian blood. ”

“ FLY SCAVENGERS
There are various kinds of insects that perform a very useful work in the world, for which they do not always receive credit. When you pass a dead Mole in the fields, and see Ants, Beetles and Flies on it, you shudder and get away from the spot as quickly as possible. You think they are horrid, dirty insects; but they are not; they are busy making the world a cleaner place for you to live in. Let us watch some of these Flies at work, and we shall get an idea of the wonderful things they do in this connection. ”

“ For the most part these insect parasites are small four-winged flies, although many of them are two-winged flies. In either case the life stages show a series of changes much like those of the butterflies themselves. Each parasite exists first as an egg, second as a larva, third as a pupa, and fourth as an adult fly. ”

“ Also, a fly when it settles remains quiet, whereas an aculeate if in a flower sets to work collecting pollen, or if basking in the sun on a leaf rarely rests for many seconds without moving in some way. On a flower, if an insect is seen quietly sitting with its head away from the centre of the {94}flower, it is almost certain to be a fly. ”

“ As you walk through a wood in summer, you may often see a black and yellow fly hovering in mid-air. If you move, it darts away so swiftly that the eye cannot follow its flight. But if you stop, and remain perfectly still, it will come back again in a moment or two, and hover just as before.
This is a hawk-fly, and it is very useful, for the mother insect always lays her eggs on twigs and leaves which are swarming with aphides. On these insects the grubs feed, so that as soon as they hatch out they find themselves surrounded with prey, and destroy the little insects in great numbers. ”

“ The fly will go all over a tree and poke its flexible wire egg-layer into countless holes. This clever creature eats very little, but spends most of its time laying eggs in the larva of moths, butterflies and beetles.
Sometimes you may see an insect that looks like a small dragon fly, but that flaps its four gauze wings, in flying. It lays eggs in tiny sand deserts in the woods, on river banks and sea shores. An innocent looking flier it is, but its larva is a true beast of prey—the cunning,flesh-eating ant-lion. ”

“ The very small black flies which are such a source of annoyance to travellers in the summer-time, and which fly into our eyes and crawl over our faces during the prevalence of warm windy weather, principally belong to a kind of insect which is characterised by having very remarkable wings when in the adult condition. These insects exist by myriads, and there are several species of them ”

“ The house-fly and the bluebottle fly also belong to the order of the Diptera. They are not very pleasant insects, but while they are grubs they are really most useful, for they feed upon [386] all sorts of decaying substances. And another insect, called the flesh-fly, is even more useful still, for it is the parent of from sixteen to twenty thousand grubs: so that if even a single fly finds the carcass of a small animal and leaves her eggs upon it, the little ones that soon hatch out will devour it in a very short time. ”

“ Fly-Catchers, although they subsist almost entirely on insects, are by no means the only insectivorous creatures in existence. They merely form a considerable branch of the Noble Society of Insect Hunters. ”

“ As soon as such expansions would be of even slight use to the insect as breathing organs, the question as to their permanency would be settled. Organs so useful both for flight and aëration of the blood would be still further developed, until they would become permanent structures, genuine wings. They would thus be readily transmitted, and being of more use in adult life during the season of reproduction, they would be still further developed, and thus those insects which could fly the best, i.e. which had the strongest wings, would be most successful in the struggle for existence. ”

“ The last insect that we can mention is a brown and gray fly known as the warble. It is very troublesome indeed to cattle, for the mother fly lays her eggs upon their backs. Then as soon as the grubs hatch, they burrow underneath the skin of the poor animals, and form large swellings there, in which they spend the whole of their lives. When they are fully fed they wriggle out through a hole in the hide, drop to the ground, burrow into it, and turn to chrysalids, from which the perfect flies appear a few months later. ”

“ This type of insect gradually gave rise to the orders which now contain the largest number of species, including the beetles, moths, and flies. In many lines of this neuropteroid branch, as it is called, the larva has become adapted to a mode of life quite different from that of the adult. Many fly larvae, for example, live in rotting organic material or live as parasites within the tissues of other kinds of insects, whereas the adult flies often feed at flowers on pollen and nectar, visiting the site of the larval habitat only to lay eggs. ”

“ In 1900 Howard's article, published in the Proceedings of the Washington Academy of Sciences, on "A Contribution to the Study of the Insect Fauna of Human Excrement," further emphasized the great danger from the presence of flies in the household, and, as the house fly is the most common fly in that locality, designated that insect especially as an enemy to health. ”

“ On one plant all six leaves had caught their prey; and on several plants very many leaves had caught more than a single insect. On one large leaf I found the remains of thirteen distinct insects. Flies (Diptera) are captured much oftener than other insects. The largest kind which I have seen caught was a small butterfly (Caenonympha pamphilus) ; but the Rev. H.M. Wilkinson informs me that he found a large living dragon-fly with its body firmly held by two leaves. As this plant is extremely common in some districts, the number of insects thus annually slaughtered must be prodigious. ”

“ But now we come to other species of birds that hunt in the air, chase their game on the wing, pursuing gnats and flies and butterflies, moths and mosquitoes and beetles. They require a short beak, but one that opens very wide and is pretty sure to catch insects as they fly—a beak, in fine, that may be depended on to work almost of itself and without an instant’s pause in the bird’s flight; a beak that, above all, is so sticky inside that as soon as an insect’s wing grazes this viscous lining it is caught [221] fast in the glue-like substance. ”

“ This insect in appearance is the same as the English stone fly, but is much more plentiful on the Thompson than I have ever seen it elsewhere; in some seasons every bush on the bank is literally covered with the flies, and later on the rocks are strewn with their dead bodies. ”

“ They breed in decaying animal matter.
-3- There is still another species, smaller than any of those so far mentioned, which is sometimes called the "lesser house fly." [7] This insect is distinguished from the ordinary house fly by its paler and more pointed body. The male, which is commoner than the female, has large pale patches at the base of the abdomen, which are translucent when the fly is seen on the window pane. These little flies are not the young of the larger flies. Flies do not grow after the wings have once expanded and dried. ”

“ The life-story of a may-fly follows the same general course as that just described for the dragon-flies, but there are some suggestive differences. In the first place, we notice a wider divergence between the imago and the larva. An adult may-fly is one of the most delicate of insects; the head has elaborate compound eyes, but the feelers are very short, and the jaws are reduced to such tiny vestiges that the insect is unable to feed. ”

“ The hind-wings are replaced by a pair of small-stalked, club-shaped ‘balancers,’ which are readily visible in some kinds of fly—e.g., the daddy-long-legs—but in others are by no means conspicuous. Thus it is an easy matter to determine whether an insect be a fly or not. To determine what particular kind of fly it be is, however, a very different affair. At present some forty thousand species of Diptera are known, and have been more or less completely described or figured ”

“ The food is chiefly insects but considerable numbers of spiders and daddy-long-legs also are eaten. Beetles, caterpillars, and ants are the larger classes of insect food, but moths, flies, bugs, and a few hymenoptera also are eaten. Among forest enemies that have been found in stomachs of this species are round-headed wood borers, leaf beetles, flea beetles, weevils, bark beetles, leaf hoppers, and jumping plant lice. ”

“ Our readers will understand, then, that all flies, like our mosquito for example, grow while in the larva and pupa state, and after they acquire wings do not grow, so that the small midges are not young mosquitoes, but the adult winged forms of an entirely different species and genus of fly; and the myriads of small flies, commonly supposed to be the young of larger flies, are adult forms belonging to different species of different genera, and perhaps of different families of the suborder of Diptera. ”

“ Hurt a fly! He would not for the world: he’s pitiful To flies even. ‘Sing,’ says he, ‘and teaze me still, If that’s your way, poor insect.’ That's your way! ”

“ A brown spotted lady-bug climbed the dizzy height of a grass blade, and Tom bent down close to it and said, "Lady-bug, lady-bug, fly away home, your house is on fire, your children's alone," and she took wing and went off to see about it —which did not surprise the boy, for he knew of old that this insect was credulous about conflagrations, and he had practised upon its simplicity more than once. ”