Fluid, s. In physic, an animal juice; any thing that flows.
Flush, v. To colour, to redden; to elate; to spring birds.
Flush, s. Afflux, sudden impulse, violent flow; cards all of a sort.
Flutter, v. To take short flights with great agitation of the wings; to move irregularly.
Fly, v. To move through the air with wings; to pass through the air; to pass swiftly; to fly at; to burst asunder with a sudden explosion; to shiver; to run away; to attempt to escape.
Fly, s. A small winged insect; that part of a machine which, being put into a quick motion, regulates the rest.
From my own experience I should suppose that in all the habitable parts of the globe, certain water-flies exist wherever there is running water. Even in the most ardent temperature, gnats and musquitoes are found, which lay their congeries of eggs on the water, which, when hatched, become, first worms, afterwards small shrimp-like aurelia, and, lastly, flies. There are a great number of the largest species of these flies on stagnant waters and lakes, which form a part of the food of various fishes, principally of the carp kind; but the true fisherman’s fly—those which are imitated in our art—principally belong to the northern, or at least temperate parts of Europe, and I believe are nowhere more abundant than in England. It appears to me, that since I have been a fisherman, which is now the best part of half a century, I have observed in some rivers where I have been accustomed to fish habitually, a diminution of the numbers of flies. There were always some seasons in which the temperature was favourable to a quantity of fly; for instance, fine warm days in spring for the grannam, or brown-fly; and like days in May and June for the alder-fly, May-fly, and stone-fly: but I should say, that within the last twenty years I have observed a general diminution of the spring and autumnal flies, except in those rivers which are fed from sources that run from chalk, and which are perennial—such as the Wandle, and the Hampshire and Buckinghamshire rivers; in these streams the temperature is more uniform, and the quantity of water does not vary much. I attribute the change of the quantity of flies in the rivers to the cultivation of the country. Most of the bogs or marshes which fed many considerable streams are drained; and the consequence is, that they are more likely to be affected by severe droughts and great floods—the first killing, and the second washing away the larvæ and aurelias. May-flies, thirty years ago, were abundant in the upper part of the Teme river, in Herefordshire, where it receives the Clun: they are now rarely seen.
In December and January there are a few small gnats or waterflies on the water in the middle of the day, in bright days, or when there is sunshine. These are generally black, and they escape the influence of the frost by the effects of light on their black bodies, and probably by the extreme rapidity of the motions of their fluids, and generally of their organs. They are found only at the surface of the water, where the temperature must be above the freezing point. In February a few double-winged water-flies which swim down the stream are usually found in the middle of the day—such as the willow-fly; and the cow-dung fly is sometimes carried on the water by winds. In March there are several flies found on most rivers. The grannam or green-tail fly, with a wing like a moth, comes on generally morning and evening, from five till eight o’clock, A. M. in mild weather in the end of March and through April. Then there are the blue and brown, both ephemeral, which come on, the first in dark days, the second in bright days; these flies, when well imitated, are very destructive to fish. The first is a small fly with a palish yellow body, and slender, beautiful wings, which rest on the back as it floats down the water. The second, called the cob in Wales, is three or four times as large, and has brown wings, which likewise protrude from the back, and its wings are shaded like those of a partridge, brown and yellow-brown. These three kinds of flies lay their eggs in the water, which produce larvæ that remain in the state of worms, feeding and breathing in the water till they are prepared for their metamorphosis and quit the bottoms of the rivers, and the mud and stones, for the surface, and the light and air. The brown fly usually disappears before the end of April, likewise the grannam; but of the blue dun, there is a succession of different tints, or species, or varieties, which appear in the middle of the day, all the summer and autumn long. These are the principal flies on the Wandle—the best and clearest stream near London. In early spring these flies have dark olive bodies; in the end of April and beginning of May they are found yellow; and in the summer they become cinnamon-coloured; and again, as the winter approaches, gain a darker hue. I do not, however, mean to say that they are the same flies, but more probably successive generation of ephemera of the same species. The excess of heat seems equally unfavourable as the excess of cold, to the existence of the smaller species of water insects, which, during the intensity of sunshine, seldom appear in summer, but rise morning and evening only. The blue dun has, in June and July, a yellow body; and there is a water-fly which in the evening is generally found before the moths appear, called the red spinner. Towards the end of August, the ephemera appear again in the middle of the day—a very pale, small ephemera, which is of the same colour as that which is seen in some rivers in the beginning of July. In September and October, this kind of fly is found with an olive body, and it becomes darker in October, and paler in November. There are two other flies which appear in the end of September, and continue during October, if the weather be mild; a large yellow fly with a fleshy body and wings like a moth, and a small fly with four wings, with a dark or claret-coloured body, that when it falls on the water has its wings like the great yellow fly, flat on its back. This, or a claret-bodied fly, very similar in character, may be likewise found in March or April, on some waters. In this river I have often caught many large trout in April and the beginning of May, with the blue dun, having the yellow body; and in the upper part of the stream below St. Alban’s, and between that and Watford, I have sometimes, even as early as April, caught fish in good condition; but the true season for the Colne is the season of May-fly. The same may be said of most of the large English rivers containing large trouts, and abounding in May-fly: such as the Test and the Kennet; the one running by Stockbridge, the other by Hungerford. But in the Wandle at Carshalton and Beddington, the May-fly is not found: and the little blues are the constant, and, when well imitated, killing flies on this water; to which may be joined a dark alder fly, and a red evening fly. In the Avon, at Ringwood and Fordingbridge, the May-fly is likewise a killing fly; but as this is a grayling river, the other flies, particularly the grannam and blue and brown, are good in spring, and the alder-fly or pale blue later, and the blue dun in September and October, and even November. In the streams in the mountainous parts of Britain, the spring and autumnal flies are by far the most killing. The Usk was formerly a very productive trout stream, and the fish being well fed by the worms washed down by the winter floods, were often in good season, cutting red in March and the beginning of April: and at this season the blues and browns, particularly when the water was a little stained after a small flood, afforded the angler good sport.
As we are on the subject of tying, I must observe, that the advantage one derives from being able to construct his own flies is wonderful; in fact, without attaining this accomplishment in the ‘gentle art,’ no one can fish comfortably or successfully. No stock, however extensive, will afford a supply adapted for every change of weather and water, and a man may lose a day overlooking an interminable variety of kinds and colours, in a vain search after one killing fly. Not so the artist: the favourite insect being once ascertained, he speedily produces an imitation and fills his basket, while his less fortunate neighbour is idly turning the pages of his over-stocked fishing-book.