Hal.—I wish it was in my power to give you information from my own experience, but, I am sorry to say, this has been very limited; and though the English are peculiarly the fly fishing nation, yet our philosophical anglers have not contributed much to this department of science, and what has been done is principally by foreigners, amongst whom Swammerdam, Reaumur, and above all De Geer, are pre-eminent. To attempt to collect and apply the knowledge accumulated by these celebrated men, would carry us far beyond the limits of a day’s conversation; and as a great proportion of the insects that fly, walk, or crawl, are the food of fishes, a dissertation, or discourse on this subject, would be almost a general view of natural history. You know that frogs, crawfish, snails, earthworms, spiders, larvæ of every kind, millipedes, beetles, squillæ, moths, water flies, and land flies, are all eaten by trout; and I once heard the late Sir Joseph Banks say, that he found a large toad stuck in the throat of a trout; but as the skin of this animal is furnished with an exceedingly acrid secretion, it probably had been disgorged after being swallowed by a fish exceedingly hungry. But though I have found most of the insect tribes, and many small fishes, even of the most ravenous kind, as pike, in the stomachs of trout, it never happened to me to see a toad there. I might give you an account of the birth and life of frogs, which, with respect to their generation, resemble fish, and which, when first excluded from the egg, may be considered in the tadpole state as fish; and you would not find their singular metamorphosis without interest. Or I could detail to you the true histories which naturalists have given of the habits of snails and earthworms, and of the sexual relations of these apparently contemptible animals;—but this is too delicate a subject to dwell on. Even the renewing or change of shell in the crawfish, when it falls in its soft state an easy prey to fish, is a curious inquiry not only for the physiologist, but likewise for the chemist. On these points, I must request you to refer to writers in Natural History: yet I shall perform my promise, and say a few words on winged insects, which, in their origin and metamorphosis, offer the most extraordinary known miracles perhaps of terrestrial natures. You must be acquainted with the origin of our common house flies?
Phys.—We know, that they spring from maggots, and that both the common and blue bottle fly deposit their ova in putrid animal matter, were the eggs are hatched and produce maggots, that, after feeding upon the decomposing animal material, gradually change, gain a hard or horny coat, seem as if entombed, and wait in a kind of apparent death or slumber, till they are mature for a new birth, when they burst their coatings and appear in the character of novel beings—fitted to inhabit another element.
Hal.—The history of the birth and metamorphosis of all other winged insects is very similar, but with peculiarities dependent upon their organs, wants, and habits. You know the curious details with which we have been furnished by natural historians of bees and ants, which live in a kind of society. The ant flies, of which, as I mentioned to you, imitations are sometimes used by fishermen, were originally maggots, and became furnished with wings—not, however, passing through the aurelia state for this last transformation.
Poiet.—I beg your pardon, but, having lately read an account of these animals in the very interesting book, called “An Introduction to Entomology,” I think I can correct you in one particular; which is, that the maggot of the ant does assume the form of a chrysalis or pupa, before it becomes a winged animal.
Hal.—It is true, that the immediate transition of the maggot is into a pupa, then into an ant, which is furnished with a kind of case, from which the wings emerge for their perfect transformation into the fly or imago state. The males die soon after the sexual intercourse; the females, when impregnated, lose their wings, and either voluntarily or by force enter into society with neuter or working ants, for the purpose of raising a new generation.
Poiet.—You are perfectly right; and though it would be irrelevant to our present object, I could almost wish, for the sake of amusing our friends, that you would detail to us some other parts of the marvellous history of these wonderful animals, which, if not so well authenticated, might be supposed a philosophical romance. Such as the neuter or working ants feeding each other and the offspring; the manner in which they make, defend, and repair their dwellings, provide their food, watch and attend to the female, and take care of her eggs; their extraordinary mode of acquiring and defending the aphides and cocci, which bear to them the same relation that cattle do to man, which are fed by them with so much care, and the milk of which forms so important a part of their food; the predatory excursions of a particular species to carry off pupa, which they bring up as slaves.
Hal.—To enter into any of the details of the history of insects in society, would carry us into an interminable, though interesting subject, that would soon lose all relation to fly fishing; and I fear what I have to say, even on the winged insects connected with this amusement, will occupy too much of your time, for we have not more than an hour to devote to this object.
Poiet.—Tell us what you please; we are attentive.
PHRYGANEÆ,
With their Imitations.