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perhaps a few days; and where the pleasures they enjoy, or the purposes for which they were produced, are in a great measure beyond the reach of our faculties to explore.
The external senses of insects, as far as we are enabled to judge of them, correspond with the low measure of sagacity which the Author of nature has assigned them. Of some senses they seem altogether destitute, while others they enjoy but in an imperfect manner. The organ of hearing is doubtful; spiders, and several other genera, give evident proofs of such an organ, though we know not where it resides, or in what it consists. In others, the existence of this sense is very equivocal, though it is probable they possess it. Many of them are endowed with the power of uttering - sounds; as the bee, the fly, the gnat, and the beetle. The sphinx atropos squeaks when hurt, nearly as loud as a mouse; it has even the power, in certain circumstances, of uttering a plaintive note, which excites commiseration. In general, the power of uttering sounds agreeable to the feelings and necessities of animals is conferred on them for the purpose of communicating such feelings to the rest of their kind. In fishes we have been able to trace that the vocal tribes are also endowed with organs for the reception of sounds; and the same, perhaps, holds with regard to insects. For why should the individual be possessed of the power of expressing its pleasures or its pain, if all knowledge of sound be denied to its gribe ? Were the sense of hearing withheld from the animals of the same class, it would crave assistance in vain; it would speak a language destined to be unintelligible to every being in nature. Experience daily convinces us of the truth of these remarks. If a bee or wasp be attacked near the hive, the usual consequence of this assault is, that the animal expresses its pain or indignation in a tone different from its ordinary hum; the complaint is
immediately understood by the hive within, when the inhabitants hurry out to revenge the insult, in such numbers that the offending party seldom comes off with impunity. The same evidence of hearing is still more obviously afforded by the spider. Often his webs are of such an enormous length, that he cannot see from the one end of them to the other; often, too, in watching for his prey he conceals himself in some adjoining crevice, where he cannot see the animal that becomes ensnared in his toils. The fly, however, no sooner finds itself entangled than it makes a buzzing noise, in order to escape; this noise is instantly heard and understood by the spider, who, sallies forth from his concealment, and riots in the spoil with all the eagerness and ferocity which distinguish the most rapacious quadrupeds.
But, besides the sense of hearing, it seems highly probable that insects possess also that of smeli. Many of them live on bodies in a state of putrefaction, around which, when exposed, they are seen immediately to collect, as though attracted by the fetid aroma; while those which feed on herbs, flowers, or fruits, seem to require a similar sense to direct them. It has hence been supposed that the palpi, or feeders, are the organs of smell in the insect tribes. These instruments are four, sometimes six in number; two of them evidently destined to the purpose of handling their food, and conveying it to the mouth. The others, which are in continual motion, and constantly applied to objects on which they alight, seem employed, like the snout of a hog, in searching for food, and examining the quality of the different kinds of sustenance by which they are supported.
The organs of vision among most kinds of insects are large; a circumstance which has put their sense of seeing beyond a doubt. These large eyes are commonly two in number, each frequently consisting of a congeries or assemblage of lenses (supposed by some to be perfect eyes in themselves), covered with a crustaceous transparent substance, to protect them from injury. In other insects, and especially in the spider tribe, these large or aggregate eyes are numerous; and in others, again, the sense of vision consists of mere stemmata of a simple structure, placed on the top of the head.
How sweet to muse upon His skill displayed
Insects are distinguished from all other animals by many peculiarities of form. None of other classes have more legs than four. But most insects have six; and many of them eight, ten, fourteen, sixteen, eighteen, and even a hundred legs. Beside the number of legs, insects are furnished with antenna, or feelers. These feelers, by which they grope and examine the substances they meet with, are composed of a greater or lesser number of articulations or joints. When a wingless insect is placed at the end of a twig, or in any situation where it meets with a vacuity, it moves the feelers backward and forward, elevates, depresses, and bends them from side to side, and will not advance further, lest it should fall. If a stick, or any other substance, be placed within reach of the feelers, the animal immediately applies them to this new object, examines whether it be sufficient to support the weight of its body, and instantly proceeds in its journey. Though most insects are provided with eyes, yet the lenses of which they consist are so small and convex, that they can see distinctly but at small distances, and, of course, must be very incompetent judges of the vicinity or remoteness of objects. To remedy this defect, they are provided with feelers, which are perpetually in motion while the animals walk. By the same instruments, they are enabled to walk with safety in the dark.
No other animals but the insect tribes have more than two eyes; but some of them have four, and others, as the spider and scorpion, have eight eyes. In a few insects, the eyes are smooth; in all the others, they are hemispherical, and consist of many thousand distinct lenses. The eyes are absolutely immoveable: but this defect is supplied by the vast number of lenses, which, from the diversity of their positions, are capable of viewing objects in every direction. By the smallness and convexity of these lenses, which produce the same effect as the object glass of a microscope, insects are enabled to see bodies that are too minute to be perceived by the human eye. Another peculiarity deserves also our notice. No animals, except a numerous tribe of four-winged insects, have more than two wings. Insects also are deprived of bones. But that defect is supplied, in some, by a membraneous or muscúlar skin, and, in others, by a crustaceous or horny covering. In this circumstance, insects resemble the shelled animals, whose bones constitute the external parts of their bodies.
În general, the bodies of insects are composed of à head, trunk, and abdomen. The head is commonly attached to the trunk by a joint or articulation. Besides eyes, feelers, and mouth, the heads of some insects are furnished with palpi fixed to the mouth;
and they are either four or six in number. Each of them consists of two, three, or four joints, and are often mistaken for the antennæ, or feelers. These instruments seem to serve the animals instead of hands; for they employ them to bring the food to their mouths, and to keep it steady while eating.
The mouth of insects is generally placed in the under part of the head; but, in some, it is situate in the breast. The jaws, instead of being horizontal, are often transverse, and furnished with teeth. The greater number of winged insects are provided with a proboscis, or trunk, an instrument by which they extract the juices from animal or vegetable substances. The proboscis of insects is a machine of a very complicated nature. In butterflies, the proboscis is situated precisely between the two eyes. Though some of them exceed three inches in length, they occupy but a small space. When a butterfly is not in quest of food, the proboscis is rolled up in a spiral form, similar to that of a watch-spring, each successive ring covering the one which precedes. The substance of the proboscis has some resemblance to that of horn. It tapers from the base to the extremity. It is composed of two similar and equal parts, each of which is concave, and, when joined, form three distinct tubes. Reaumur has rendered it probable, that these tubes enable the animals to extract the juices of plants, to conduct air into their bodies, and to convey the sensation of smelling. Hence the proboscis of insects is an instrument which serves them for a mouth, a nose, and a windpipe.
The upper part of the trunk or body of an insect is called the thorar, and the under part the abdomen, or belly. The abdomen contains the stomach and other viscera. It consists of several rings or segments, and is perforated with spiracula, or tubes, which supply the want of lungs. The abdomen is terminated by the tail, which, in some insects, is