The Natural History of the EPHEMERON, or DAY-FLY.
THERE is nothing more trite and common than the ridicule which persons unused to the study of nature endeavour to throw on those whom a more speculative turn of mind induces to follow her into her inmost recesses, and examine even into the extremest minutiae of her works. The titles of gimcrack, cockle-shell merchant, fly hunter, &c. are lavishly bestowed on them by such as either ignorance, indolence, or a natural want of curiosity, have excluded from the great garden of nature: they find no amusement or instruction in a box of cockle-shells, a bundle of weeds, or a cluster of caterpillars (for so in general terms are all the objects of natural enquiry stiled by them) and therefore conclude that neither is capable of being drawn from them; and consequently, ‘to what use is all this,’ is ever their general cry.
But the real philosopher, the man of clear reflection, and accurate discernment, who traverses every path, and explores every winding of this regular wilderness, will meet not only with entertainment, but also with great improvement from every object that he sees. Each step he takes a text presents itself, from which his genius may draw out a sermon of admirable service to his fellow-creatures. Nor can the apparent insignificance of the subjects in themselves render the lesson they convey the less important, but quite the contrary. For if in the minutest animals we perceive the care and wisdom of an infinite power exerted for their formation and protection; if we perceive them endued with all those faculties which are or can be necessary for their preservation, and those faculties even most punctually employed to the purposes for which they were intended; with what an awe and adoration ought it to turn our thoughts towards the great Creator of them all! with what gratitude should it inspire our hearts for him who has still so much more taken care for us, and bestowed on us faculties and powers so greatly superior to the rest of his creatures! and lastly, with how much self-reproach should it fill us when we consider that from a misapplication of those powers we so frequently defeat the all-wise designs of heaven, and even render them more fallible than the uncorrupted instinct even of the smallest reptile!
In short, there is no object from which the speculative man may not deduce a lesson, or on which he may not moralize with advantage. Nay, useless as the study of natural history may now appear to the unlearned, yet let them seriously reflect from whence they have acquired some of their most valuable improvements, to whom they stand indebted for their most useful arts, and they will find them owing to observations of this kind made by men in the more early periods of the world; and that the greatest part of that genius which man so proudly boasts of is very little more than the noticed instinct of other animals improved upon by his own reason.
To instance only in a very few examples.—Who taught us the art of building but the beaver? who that of spinning but the silk worm? of weaving but the spider? of navigation but the nautilus? are not the faculties of the mind also greatly to be improved by observation of other animals? can the necessity of regular subordination and strictness of government be better pointed out than in that of the bees? do not the ants instruct us in industry and frugality? or can we observe the lion-pismire without being taught a noble lesson of patience and perseverance?
But if reflection and moral contemplation are to be sought for in these researches, what object offers an ampler scope for them than the animal which I am now going to introduce to the acquaintance of my fair readert? for what can possibly afford a more just idea of the real value of time, and the necessity of employing every moment of it to the best advantage, than the observing a creature whose whole allotted period of life is no more than the space of five hours, and that in the general not half attained to, but cut off in the middle by some insidious enemy who lies in wait to destroy it?
This fly (for in the fly-state only is it to be considered in this view) is called by the authors who have written concerning it by the names of the ephemeron, hemerobios, and diaria; all which mean no more than an animal of but a single day’s existence. It is a native of Germany, and appears every year for about three days successively, fluttering on the surface of the water at the mouths of the Rhine, the Meuse, the Wael, the Leck, and the Ysel, about the middle of June. But this continued appearance of them is kept up by a regular succession; for those who begin to live and flutter about towards the noon of the first day are dead before night, a new set makes its appearance on the second, and the third in like manner is supplied by a fresh generation. After which no more of them are to be seen, till the succeeding year renews this three day’s phaenomenon.
Altho’ the life of the ephemeron in its fly-state, which we shall more particularly dwell on hereafter, is so extremely short, yet as it has an existence under another form, and in another element, which continues through a space of three years, it will be necessary that we should dwell a little on its history during that period, and relate the manner of its several changes.
In short, although this animal, when arrived at the state of full perfection, is an enlivened flutterer of the airy regions, yet his original existence is in the waters, where the eggs being deposited by the female, aed impregnated by the male, in the same manner as the spawn of fishes, are scattered over the muddy bottoms of the rivers by the motion of the water, and there deposited in that bed, which is the most proper for their being hatched and brought into life.
As these eggs are not united together by any glutinous or gelatinous substance, nor deposited in clusters as the spawn of the frog, of the watersnail, and of several other insects, but entirely dispersed and separate from each other, it is no very easy matter to ascertain how long it is before the insect contained within them acquires life, and breaks through its shelly integument. It is sufficient to observe, that after a certain period they produce a little worm, with six legs, which at one year’s growth is of the size and form represented in the annexed plate, at Fig. I. At this age it is not only without wings, or those prominences which cover the wings, but also without the least signs or vestiges of any such part. When they come to be two years old, the little sheaths of the wings appear very plainly; and the animal, then very greatly enlarged in bulk, appeas as at Fig. II. And when it has reached its third year, at which time it is to undergo its grand metamorphosis, these cases are then as conspicuous as possible, resembling a little flower that increases by degrees, and is ready to break out of its cup. Its appearance is then such as is shewn in Fig. III.
This animal is made great use of by the fishermen, by whom it is called by the name of bankbait: for although they can swim very swiftly, yet it is seldom that they do so, but are always found near the banks of rivers, and there live in the most quiet parts. The more mud there is at the bottom out of which they first rise, the greater number of the worms are usually to be met with. Yet are they very rarely to be found either lying on the mud or adhering to it; but they live within the mud or clay itself, in hollows made oblong and smooth, and which they constantly bore, not obliquely or perpendicularly, but ever parallel to the horison, each several animal living in a separate cell.
The worm of the ephemeron as soon as it hatched from the egg, prepares for the building of these cells or houses, which they make larger and larger as the size of their body increases; so that the full grown worms are always to be found in larger, the younger in smaller tubes. For this purpose nature has furnished them with parts particularly adapted thereto, their two fore-legs being formed in some measure like those of the mole, or mole cricket, and their jaws furnished with two teeth, somewhat like the forcipes or claws of crabs, which are of great service to their making their way into the mud.
If you throw some of them into a little mud mixed with water, you will instantly perceive them begin this work of piercing and boring; and if the quantity of mud you give them is not sufficient entirely to immerge them, they will nevertheless continue to undermine what they have, hiding at one time their heads, at another their bodies, and at others their tails, in the attempt to form new cells.
In these cells then the worm of the ephemeron continues, till the time when it is to undergo its final metamorphosis, which as I have before observed is at the period of three years; previous to which the cases of the wings appear very protuberant on the back, the smooth, and depressed form of the upper part of the body is changed into a more swollen and rounder shape, and the wings themselves become in some degree visible through their external skin.
At the time that this metamorphosis is to begin, which is generally about six o’clock in the evening, the worm quits his cell, and goes into the water, from the bottom of which he immediately makes all the expedition he can to the surface, and there fixing on any thing solid that he can meet with, either wood, stone, earth, a tree, a boat, a beast, or a man, all appearing equally indifferent to him, he appears to be seized all over with a shuddering or trembling motion, when immediately the skin opens on the middle of the back, the slit enlarging towards the fore parts, till it becomes so wide, that the animal is able to thrust his head out at it; after which he draws his legs also out of the skin, as in Fig. IV. whilst the claws, adhering to the cast skin, are in the mean time firmly fixed in their places, which greatly contributes towards enabling him to slip the rest of his body out of its covering. It must moreover be observed that the head and legs are stript of their skin in the same manner that we draw our feet out of our shoes; but that as to the other parts, that is to say the first and second pair of wings, the skin is drawn off from them in such a manner as that they become turned inside out, as we invert a limber pair of gloves, the inward surface or inside of the fingers being pulled out; so that the exuvium, or case which is left behind, bears the form represented at Fig. V.
When it has thus quitted its case, and consequently compleated its change, it appears a perfect fly, with two pair of very fine filmy wings, as at Fig. VI.
From this period then may be dated the commencement of its life, the whole duration of which afterwards is never more than about five hours, in which short space it generates, lays eggs, grows old, and dies. —That is to say if it even reaches to the extent of that very short allotted space; for short as it is, it is frequently cut off before the conclusion of it by the means of some of the very numerous enemies whereby this innocent unhappy little creature is persecuted in the course of it. Fond as it were of the element from whence he sprung, no sooner is his change compleated, than he instantly repairs to it again, and flutters towards its surface, where if he ventures too near, he becomes an easy prey to the trout, and many other kinds of fish, who watch to take him, and to whom he is a most delicious morsel; and if he soars higher into the air, he is as liable to be snapp’d up by the birds, who are no less fond of him. They frequently even seize and devour him whilst he is engaged in the great work of changing his skin; nay, numbers of the worms are destroyed by the inhabitants of the waters, in their very birth, before they can reach the surface to become the tenants of a purer element.
Such, so short, and so full of peril is the life of this harmless little insect; and such, O man! is thine!
