THE GNAT.
HAD the gnat been endowed with as great a power of making itself obnoxious as its first cousin the mosquito, it would have been the subject of anxious inquiry and investigation by man. As it is, it attracts but slight attention, and lives and dies in undisturbed obscurity. In this respect it closely resembles what are called the working classes among man. The noisy spouter, the obnoxious demagogue, the troublesome striker attract attention; the vast patient herd live and die almost unnoticed. There is no reason for supposing, however, that the gnat takes the neglect of man to heart, fond as he undoubtedly is of man’s companionship. In this respect he stands almost, if not quite alone among created things, for the attentions paid to man by the flea, the bug, and the mosquito are strictly selfish. Gnats, however, appear to be purely disinterested in their attentions, and to regard the doings of man with pleased and curious interest. They will attend him in his walks, flying in a cloud over his head or a pace or two in front of him; while their interest in him when engaged in fishing, sketching, or other pursuits is unbounded. They do not, like the midge, interfere with him in any other way, but keep at a respectful distance. A young couple strolling through a lane as the shades of evening are falling are a spectacle specially attractive to gnats. They will frequently on such occasions form themselves into filmy clouds, rising and falling in rhythmical measure, expressive of satisfaction and goodwill.
The summer evening gnat must not be confused with a cousin of his which occasionally infests low-lying and marshy neighbourhoods. This bears both in point of size, appearance, and habits, a much closer relation to the mosquito than to the gnat, and it may, indeed, be termed the English mosquito. It is many times larger than the gnat which is the subject of our remarks, has dark limbs and body, a stinging proboscis, and a bare head. The gnat is scarce more substantial than a cobweb, and has upon its head a lovely plume. It is silent, or, at least, if it utters a sound, its vibrations are too rapid for the ears of man to detect.
The life of the gnat, although short, would seem to be more full of pleasure and enjoyment than that of any other creature. Other insects that consort together in large numbers do so for mutual convenience or protection. Multitudes are needed for the various work of the bee, wasp, and ant cities. Caterpillar communities dwell together, partly because they were born so, but probably more because the web, their common work, is a protection against their enemies, and specially against their most deadly foe, the ichneumon. The aphis feed crowded in close herds, but their power of locomotion is so small that they live and die where they were born. Gnats, however, congregate simply to enjoy the companionship of their friends. Their gatherings are great balls and dances. Flying in a soft cloud scarce more palpable than steam, and ever changing in form, they rise and fall in constant motion, and it is impossible to doubt that this action partakes, to some extent, of the character of a dance. A faint, low hum accompanies the motion, caused partly, perhaps, by the beating of the innumerable gossamer wings, partly by the whispered conversation or song from innumerable throats. Naturalists have puzzled themselves in vain for any explanation of the object of these dancings. The natural one, that it is the outcome of a joyous and happy disposition, an exercise expressive of pleasure and happiness, is too simple to be received with approval by the scientific mind.
Man does not so rejoice in his existence. He has not such unbounded satisfaction in the companionship of multitudes of his fellows, nor throughout all nature is there any parallel to the great gatherings and dancings of the gnats. Flies, indeed, do join in sportive chases and flights, but these are engaged in by few individuals only. Flights of starlings and some other gregarious birds approach more nearly to the gnat assemblies, and are also frequently marked by rhythmical fallings and risings; but they are comparatively short outbursts of playful joyousness, and not comparable with the constant and prolonged dances in which the gnat spends the greater portion of its existence as a perfect insect. Well may the gnat be transparent, for it is doubtful whether it takes any solid food from the time of its emergence from its pupa case to that when, its existence terminated, it drops lifeless on the surface of a stream. It drinks, however, and a dewdrop is sufficient to afford refreshment to thousands.
The gnat’s life, like that of most insects, is a dual one; but unlike most others, the first—and much the longest portion—is spent in the water. The female gnat selects some quiet and sheltered piece of water, a stagnant pool for preference, and lays her eggs upon its surface. In form they may be compared to long small-bore bullets, pointed at the upper end. They are placed closely together and adhere lightly to each other, and when the tiny mass is examined through a magnifying glass it presents the appearance of a honeycomb studded with tiny points. If no accident befall it, the little raft floats until the young ones are ready to take to the water; then the lower ends of the tiny tubes open and the larvæ swim away. Their life in the water resembles that of most other aqueous creatures. They feed upon organisms even more diminutive than themselves, and are the prey of the smaller water beetles and tiny fish. The gnat larva obtains the animalculæ on which it feeds by means of two ciliated organs on the head. These are in constant motion, and create a current by which its food is drawn into its mouth. But, though an inhabitant of the water, the gnat even in this stage is obliged to breathe, and therefore frequently ascends close to the surface, where it draws in the air through a little tube situated at the apex of the body.
At the end of about fifteen days this state of its existence is completed, and it assumes the pupa state. It is now doubled up, and somewhat rounded in form, but it is, nevertheless, still active; it still breathes, drawing in the air by two little tubes, situated now on the anterior part of the body. When the perfect insect is formed inside the pupa case, the air contained within the latter causes it to float on the surface. The gnat breaks through the upper side and stands upon the skin it has quitted, which serves as a little raft until it has attained sufficient strength to fly. This is the most critical moment of the gnat’s existence; the fluid in which it has lately existed would now be fatal to it, and the tiniest ripple caused by a breath of wind, or the passage close by of a fish or water beetle, before the gnat has gained strength to fly, would upset the boat and drown its occupant.
Man has not been able to solve the problem whether thought as well as life is continuous during the three stages of existence of the gnat, or, indeed, in those of any other insect; and knows not whether the gnat has any remembrance of the very different existence it passed beneath the surface of the water over which, in its perfect state, it delights to disport itself. The fact that all insects deposit their eggs in situations unsuitable for their own existence, but suitable for that of the larvae, is no proof for or against the theory, since it may be the result of blind instinct only.
Whether man will ever be able to place himself sufficientlyen rapportwith the lower creation as to be able to solve this and many other problems must be left to future ages to determine. So far, able as he is to acquire with more or less difficulty the languages of all other varieties of man, he has failed signally in comprehending that of even the birds and animals with whom he is most in contact. The dog and the horse are in this respect distinctly his superior, and the former, when admitted to close companionship, unquestionably understands at least the gist of his master’s words. As it is not the custom of the gnat to waste its strength by travelling ahead in a straight line, we have no means of determining the actual rate of speed at which it can fly. That it is very great is certain. A swarm of gnats caught in a heavy rain-shower will continue their gyrations apparently undisturbed, their sight and movement being so quick that they are able to dodge the raindrops in their descent; and at the termination of the storm, however heavy, their numbers will be apparently undiminished. This would seem to show an amount of speed and activity relatively unrivalled in any other living creature.