Fly (organism)

“ These insects immediately approach the fauces of the leaves, and, leaning over their edges, appear to sip with eagerness something from their internal surfaces. In this position they linger; but at length, allured as it would seem by the pleasure of taste, they enter the tubes. The fly which has thus changed its situation will be seen to stand unsteadily; it totters for a few seconds, slips, and falls to the bottom of the tube, where it is either drowned or attempts in vain to ascend against the points of the hairs. The fly seldom takes wing in its fall and escapes. ”

“ When the butterfly plunges its long tube into the flower—when the fly intoxicates itself with a drop of syrup, using its proboscis to pump it up—and when the flea thrusts its rostrulum into our flesh, and quaffs our life-blood as though it were nectar,—let us not forget the mouth is the organ employed in each of these cases, varied and altered in form though it certainly be. ”

“ The illustrious observer, who had already made all these discoveries on the formation and functions of the trunks of insects, often reflected on the fact that the liquors of which flies are most fond are enclosed under the skin of certain fruits, such as pears, plums, grapes, &c., or even under the skin of some animals of which they suck the blood. In order that the trunk of a fly may act under such circumstances, it is necessary for it to pierce and open the skin. If this is the case, flies ought to be possessed of a lancet. ”

“ The omnivorous habits of the house-fly are matters of everyday observation. From our view point, it is sufficient to emphasize [Pg 150] that from feeding on excrement, on sputum, on open sores, or on putrifying matter, the flies may pass to the food or milk upon the table or to healthy mucous membranes, or uncontaminated wounds. There is nothing in its appearance to tell whether the fly that comes blithely to sup with you is merely unclean, or whether it has just finished feeding upon dejecta teeming with typhoid bacilli. ”

“ The moment the fly touches the nose they shake the head, stamp with the feet, and gallop off with the nose close to the ground, looking from side to side to see if the fly pursues and frequently smelling at the grass as if apprehensive of other flies hidden there. ”

“ I must tell you now that the fly can get the typhoid germ or plant only from human filth.
Note.—The teacher should have an inexpensive microscope and show the children a fly,—its head and its feet especially.
6. Have you ever seen a fly under a magnifying glass? On the bottom of the fly's feet are little glue-like pads and a number of little hairs on his body and feet, to which germs and bits of dirt stick. The fly in this story had come to the farm-house for the first time, you know, when he found the pitcher of milk and had such a nice bath. ”

“ When this fly attacks an animal, or man, it pierces the skin instantaneously, like the prick of a red-hot needle driven deep into the flesh, at the same time the insect exerts every muscle of its body by buzzing with its wings as it buries the instrument to its greatest depth. ”

“ Perhaps it is this cool, sparkling appearance which attracts the insects to it, but when once a fly alights on one of the leaves, its fate is sealed. The tentacles with their sticky tips bend over one by one till the fly is quite covered in by them and cannot get away. It dies, and is digested by the juices given out by the leaf, which are very much like the digestive juices of animals. ”

“ The worm of the fly has a pair of jaws like hooks. It has two little dots which will become eyes when it has grown to a fly. In the hooked jaws and these eye-points it is not like an earth-worm.
The fly grub eats and grows. Then its skin gets tough and hard, and forms a little case like a barrel. This shuts the worm in it, as in a coffin. Now the baby fly seems to be dead.
But it is not dead. It is turning into a creature that has wings and legs, and can fly and walk.
As the fly lies in its case, first the legs and then the wings grow. ”

“ Flies were placed on many leaves, and excited the glands to secrete copiously; the secretion always becoming acid, though not so before. After a time these insects were rendered so tender that their limbs and bodies could be separated by a mere touch, owing no doubt to the digestion and disintegration of their muscles. The glands in contact with a small fly continued to secrete for four days, and then became almost dry. ”

“ The new-born fly remains for some minutes motionless upon the water, then gradually revives, and feebly shakes its wings, then moves them quicker, and attempts first to walk, then to fly. As [Pg 344] these insects are all hatched nearly at the same time, they are seen in swarms for a few hours flitting and playing upon the surface of the water; they then lay their eggs, and soon after die. ”

“ Fig. 30 is one of the balancers or “haltéres” of the house-fly. These organs are found in all the two-winged insects, and are evidently modifications of the second pair of wings. They are covered with little vesicles, and protected at their base by scales. Some writers suppose that the sense of smell resides in these organs. Whatever other purpose they may serve, they clearly aid in the flight, as, if the insect be deprived of one or both of the balancers, it has the greatest difficulty in steering itself through the air. ”

“ The fly—with its large globular head, bearing the extensive compound eyes, the highly modified feelers with their exquisitely feathered slender sensory tips, and the complex suctorial jaws; with its compact thorax bearing the glassy fore-wings alone used for flight, though the hind-wings modified into tiny drumstick-like 'halters' are the organs of a fine equilibrating sense—is perhaps the most specialised, structurally the 'highest' of all insects. ”

“ The fly is the insect of quickest flight, therefore a degree of intrigue is necessary. This is managed by running past the victim slowly, and apparently in an unconcerned manner, until the poor fly is caught unawares, and carried off by the Mellinus to its burrow. The first fly being deposited, an egg is laid. ”

“ The details are briefly as follows:—A female fly lays a few, very large, eggs, out of each of which comes a larva, that does not go on to the perfect state, but produces in its interior young larvae that, after consuming the interior of the body of the parent larva, escape by making a hole in the skin, and thereafter subsist externally in a natural manner. ”

“ The wing of the May-fly flapping in the air is a respiratory organ, of as much importance to the wellbeing of the creature in its way, as the gill-plate of its grub prototype is when vibrating under the water. But the wing of the insect is not the only respiratory organ: its entire body is one vast respiratory system, of which the wings are offsets. The spirally-lined air-vessels run everywhere, and branch out everywhere. The insect, in fact, circulates air instead of blood. ”

“ When we add to these the larvæ of flies and water beetles, the Crustaceans, Hydræ and Water Spiders, we must begin to realise that there are other things than a drowned natural fly for which the fish might mistake its imitation, with the materials of which it is made soaked in and drawn through the water. ”

“ This organ is seen under a very high power to be covered with long hair-like appendages, each having a little disc at the end, and probably secreting some glutinous fluid which will enable the creature to hold on to perpendicular and smooth surfaces. Many of my readers will doubtless have noticed the common fly, towards the end of autumn, walking stiffly upon the walls, and evidently detaching each foot with great difficulty, age and infirmity having made the insect unable to lift its feet with the requisite force. ”

“ The fly serves for food for many birds, and fish and frogs, and some insects. Some of these things [Pg 68] we use for our food. Others are full of beauty, or are of use to us, each in its own way.
Thus, though the fly is often a trouble to us, we find it is not without its uses. Look at one of these little creatures through a glass that will magnify it. You will see that the poor insect has really much beauty. ”

“ In general the house fly and other species which breed in vegetable matter are attracted to vegetable substances, while the blowflies will come most readily to animal matter. This rule, of course, is not absolute, as flies are less restricted in feeding than in breeding habits, and, as is well known, the house fly is attracted to a greater or less extent to any moist material, especially if it has an odor. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ Insects, bats, and birds are as heavy, bulk for bulk, as most other living creatures, and flight can be performed perfectly by animals which have neither air-sacs nor hollow bones; air-sacs being found in animals never designed to fly. Those who subscribe to the heated-air theory are of opinion that the air contained in the cavities of insects and birds is so much lighter than the surrounding atmosphere, that it must of necessity contribute materially to flight. ”

“ 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. ”

“ Most insects walk as well as fly, and their walking is not less wonderful than their flight. Fig. 4 represents the foot of a fly. It will be seen, under a strong microscope, to have a pair of large claws and a pair of leaf-like plates, one on each side. The claws and the plates have different uses. The plates are used when the fly is walking, say, up a window-pane or along a ceiling. ”

“ Plant fresh grass seed and grain occasionally in the cricket corner of your terrarium.
4. If you do not own an insect net, try to find a lace-winged fly without one. It will not be difficult for young naturalists to see the flies resting on the bushes along the roadside. These insects are valuable to farmers because their children, the aphis-lions, eat so many plant-lice and other insects.
Fig. 345. Golden-eyes or lace-winged fly; eggs, larva or aphis-lion, cocoon, adult. ”

“ If we shut up a blue meat-fly in a glass vase, as Réaumur did, and place near the insect a piece of fresh meat, before half a day is passed, the fly will have deposited its eggs thereon one after the other, in irregular heaps, of various sizes. ”

“ It is a fact, however, that it is possible, provided your fly book is passably well filled with various patterns, to approximate very closely the appearance of many of the natural insects you will see upon the water. ”

“ The fly lays her eggs in the manure-pile or some other filthy place. All the germs—all the microbes—fasten themselves on the spongy feet. The fly brings them into the house and wipes them off. The fly that you see walking over your food is covered with filth and germs.
TRACKS OF A FLY, SHOWING THE WAY IN WHICH THEY SPREAD DISEASE GERMS
If there is any dirt in your house, or about your premises, or those of your neighbors, he has just come from it. ”

“ When a fly is captured, the viscid excretion becomes strongly acid and the naturally incurved margins of the leaf curve still further inwards, rendering contact between the insect and the leaf-surface more complete. ”

“ Will you wonder that there are so many flies when I tell you that one fly can in one season be the mother of two million others!
Many insects die soon after laying eggs. Bees and wasps do not, nor do flies. Bees and wasps take care of their eggs and their young, but the fly mother does not. ”

“ But as for that they're no more so than the flies. How it may be with flies, I can't say, if they get the gout, or feel giddy, or what. But never hit out at a fly, for 'twill only make him worse—remember that, boys! ”

“ The membranous wings of the adult fly appear to be two in number, a second pair being reduced to tiny knobbed hairs called balancers. The head is freely movable, with large compound eyes. The mouth parts form a proboscis, which is tonguelike, the animal obtaining its food by lapping and sucking. The foot shows a wonderful adaptation for clinging to smooth surfaces. Two or three pads, each of which bears tubelike hairs that secrete a sticky fluid, are found on its under surface. It is by this means that the fly is able to walk upside down, and carry bacteria on its feet. ”