_Orn._--Surely the May-fly season is not the only season for day-fishing in this river? [the Wandle.]--_Hal._ Certainly not. There are as many fish to be taken, perhaps, in the spring fishing; but in this deep river they are seldom in good season till the May-fly has been on, and a fortnight hence they will be still better than even now. In September there may be good fish taken here; but the autumnal flies are less plentiful in this river than the spring flies--_Phys_, Pray tell me what are the species of fly which take in these two seasons.--_Hal_. You know that trout spawn or deposit their ova, &c. in the end of the autumn or beginning of winter, from the middle of November till the beginning of January, their maturity depending upon the temperature of the season, their quantity of food, &c. They are at least six weeks or two months after they have spawned before they recover their flesh; and the time when these fish are at the worst, is likewise the worst time for fly-fishing, both on account of the cold weather, and because there are fewer flies on the water than at any other season. Even in December and January there are a few small gnats or water-flies 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 the brown, both ephemerae, 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 larvae 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 light and air. The brown fly usually disappears before the end of April, likewise the grannam; but of the blue dun there is a