eggs under his skin, where the larvæ feed. Other caterpillars insinuate themselves into different cavities of his body. All the inferior animals have their peculiar parasitical insects, which feed on them during their life. There are some insects which can feed only on one species. Many caterpillars, both of moths and butterflies, feed on the leaves of some particular vegetable, and would die, could they not obtain this. There are others which can make use of two or three kinds of vegetables, but which never attain full perfection, except when they are fed on one particular kind; for example, the common silk-worm eats readily all the species of mulberry, and even common lettuce, but attains its greatest size, and produces most silk, when fed on the white mulberry. There are a great many which feed indiscriminately on a variety of vegetables. Almost all herbivorous insects eat a great deal, and very frequently; and most of them perish, if deprived of food but for a short time. Carnivorous insects can live a long while without food, as the carabus, ditiscus, &c. As many insects cannot transport themselves easily, in quest of food, to places at a distance from one another, nature has furnished the perfect insects of many species with an instinct, which leads them to deposit their eggs in situations where the larve, as soon as hatched, may find that kind of food which is best adapted to their nature. Most of the butterflies, though they flutter about, and collect the nectareous juice of a variety of flowers, as food for themselves, always deposit their eggs on or near to those vegetables which are destined, by nature, to become the food of their larvæ. The various species of ichneumon deposit their eggs in the bodies of those insects on which their larvæ feed. (See Ichneumon.) The sirex and sphex are likewise careful to deposit their eggs in situations where their larvæ, when hatched, may find subsistence. The sphex figulus deposits its eggs on the bodies of spiders which it has killed, and enclosed in a cell composed of clay. Some insects, at different periods of their existence, make use of aliment of very different properties; the larvæ of some are carnivorous, while the perfect insect feeds on the nectareous juice of flowers, e. g. sirex, ichneumon, &c. The larvæ of most of the lepidopterous insects feed on the leaves and young shoots of vegetables, while the perfect insects either take no food at all, or subsist on the sweet juice which they extract from flowers: indeed, the construction of their mouths 4

VOL. VII.

prevents them from taking any other than fluid food. We shall now refer to the functions of insects, beginning with respiration, which is the act of inhaling and exhaling the air into and out of the lungs. Mammalia, birds, and most of the amphibia, breathe through the mouth and nostrils. The air, when received into the lungs, is mixed with the blood, and imparts to it something necessary, and carries off something noxious. Some authors have asserted that insects have no lungs; but later experiments and observations show that no species is without them, or, at least, something similar to them; and, in many insects, they are larger in proportion to their bodies than in other animals. In most of them, they lie at or near the surface of the body, and send out lateral pores or trachea. The respiration of insects has attracted the attention of many naturalists; and it is found that insects do not breathe through the mouth or nostrils; that there are a number of vessels, for the reception of air, placed along on each side of the body, commonly called spiracula, which are subdivided into a number of smaller vessels, or bronchiæ; that the ves-sels, or trachea, which proceed from the pores on the sides, are not composed of a simple membrane, but are tubes formed of circular ruga; that the spiracula are distinguishable, and are covered with a small scaly plate, with an opening in the middle like a button-hole, which is furnished with membranes, or threads, to prevent the admission of extraneous bodies. Insects are the only animals without vertebræ, in which the sexes are distinguished. Copulation is performed in them by the introduction of the parts of generation of the male into those of the female. All insects are either male or female, except in a few of the genera of the order hymenoptera, such as the bee, ant, &c., where individuals are to be found, which are neither male nor fe male, and, on that account, called neuters Among the bees, the neuters form the far greater part of the community, and perform the office of laborers. Among the ants, the neuters are very numerous, and constitute the only active members of the society. It has been alleged, that these neuters are nothing but females, whose parts have not been developed for want of proper nourishment. Oliver, however, after strict examination, is disposed to think them really different, though he does not adduce facts sufficient to establish his opinion. The parts which dis tinguish the male from the female may be

divided into two classes, viz., 1. those which are not directly connected with generation; 2. those which are absolutely necessary for the purposes of generation. The circumstances which have no direct communication with generation, which serve to point out the distinction between the sexes, are the difference of size observable in the male and female; the brightness of the color in each; the form and number of articulations of the antennæ; the size and form of their wings; the presence or absence of a sting. The male is always smaller than the female; the female ant is nearly six times larger than the male the female cochineal is from 12 to 15 times the size of the male; the female termes is 200 or 300 times the size of the male; the colors of the male are commonly much more brilliant than those of the female; this is particularly the case in lepidopterous insects; in some insects, the color of the male is totally different from that of the female: the antennæ of the male are commonly of a different form, and larger than those of the female frequently the males are furnished with wings, while the females have none; the lampyris, coccus and blatta, and several moths, afford an example of this: the female bee is furnished with a sting, while the male is destitute of one: the males of some insects are furnished with sharp, prominent points, resembling horns, situated either on the head or breast, which are either not perceptible, or very faintly marked, in the female. The parts essential to generation afford the best distinguishing mark; in most insects, they are situated near the extremity of the rectum; by pressing the abdomen near to the anus, they may frequently be made to protrude; but the parts of generation are not always situated near the anus; in the spiders, they are situated in the feelers; in the libellula, the male organ is situated in the breast, while that of the female is placed at the anus. The eggs of insects are of two sorts; the first membranaceous, like the eggs of the tortoise and the other reptiles; the other covered with a shell, like those of the birds. Their figure varies exceedingly; some are round, some elliptical, some lenticular, some cylindrical, some pyramidal, some flat, some square; but the round and oval are the most common. The eggs of insects seldom increase in size, from the time they have been deposited by the parent till they are hatched: those of the tenthredo, however, and of some others, are observed to increase in bulk.

At first, there is nothing to be perceived in the eggs of insects but a watery fluid; after some little time, an obscure point is observable in the centre, which, according to Swammerdam, is not the insect itself, but only its head, which first acquires consistence and color; and the same author alleges, that insects do not increase in bulk in the egg, but that their parts only acquire shape and consistence. Under the shell of the egg, there is a thin and very delicate pellicle, in which the insect is enveloped, which may be compared to the chorion and amnios, which surround the fœtus in quadrupeds. The little insect remains in the egg till the fluids are dissipated, and till its limbs have acquired strength to break the egg and make its escape; the different species of insects remain enclosed in the egg for very different periods; some continue enclosed only a few days, others remain for several months. The eggs of many insects remain without being hatched during the whole winter, and the young insects do not come forth from them till the season at which the leaves of the vegetables, on which they feed, begin to expand. When the insects are ready to break their prison, they commonly attempt to pierce the shell with their teeth, and form a circular hole, through which they put forth first one leg, and then another, till they extricate themselves entirely. Insects afford nourishment to a great number of the superior animals; many of the fishes, reptiles and birds, draw the principal part of their sustenance from that source. The immense swarms of different species of crab, which abound in every sea, directly or indirectly form the principal part of the food of the cod, haddock, herring, and a great variety of fishes.

The snake, lizard, frog, and many other reptiles, feed both on land and aquatic insects. Gallinaceous fowls, and many of the small birds, &c., feed on insects. Swallows, indeed, feed entirely on winged insects. They afford food, likewise, to many of the mammalia, viz., to many species of the bat, to the ant-eater, &c., and even to man himself. Many species of crab, viz., lobster, common crab, shrimp, prawn, land-crab, &c., are reckoned delicacies. The larvae of some coleopterous insects and locusts form part of the food of man. Insects, likewise, by consuming decayed animal and vegetable matter, which, if left to undergo the putrefactive process on the surface of the ground, might taint the atmosphere with pestilential vapors, preserve the air pure for the respiration of man and other ani

mals. On the other hand, the injuries which they inflict upon us are extensive and complicated; and the remedies which we attempt, are often aggravations of the evil, because they are directed by an ignorance of the economy of nature. The little knowledge which we have of the modes by which insects may be impeded in their destruction of much that is valuable to us, has probably proceeded from our contempt of their individual insignificance. The security of property has ceased to be endangered by quadrupeds of prey, and yet our gardens are ravaged by aphides and caterpillars. It is somewhat startling, to affirm that the condition of the human race is seriously injured by these petty annoyances; but it is perfectly true, that the art and industry of man have not yet been able to overcome the collective force, the individual perseverance, and the complicated machinery of destruction which insects employ. A small ant, according to a most careful and philosophical observer (Humboldt), opposes almost invincible obstacles to the progress of civilization in many parts of the equinoctial zone. These animals devour paper and parchment; they destroy every book and manuscript. Many provinces of Spanish America cannot, in consequence, show a written document of a hundred years' existence. "What developement," he adds, "can the civilization of a people assume, if there be nothing to connect the present with the past; if the depositories of human knowledge must be constantly renewed; if the monuments of genius and wisdom cannot be transmitted to posterity?" Again, there are beetles which deposit their larvæ in trees, in such formidable numbers, that whole forests perish beyond the power of remedy. The pines of the Hartz have thus been destroyed to an enormous extent; and at one place in South Carolina, at least 90 trees in every 100, upon a tract of 2000 acres, were swept away by a small, black, winged bug. Wilson, the historian of American birds, speaking of the labors of the ivory-billed wood-pecker, says, "Would it be believed that the larvæ of an insect, or fly, no larger than a grain of rice, should silently, and in one season, destroy some thousand acres of pine trees, many of them from two to three feet in diameter, and 150 feet high? In some places, the whole woods, as far as you can see around you, are dead, strip⚫ped of the bark, their wintry-looking arms and bare trunks bleaching in the sun, and tumbling in ruins before every blast." The

subterraneous larvæ of a species of beetle has often caused a complete failure of the seed-corn, as in the district of Halle in 1812. The corn-weevil, which extracts the flour from grain, leaving the husk behind, will destroy the contents of the largest storehouses in a very short period. The wire-worm and the turnip-fly are dreaded by every farmer. The ravages of the locust are too well known not to be at once recollected, as an example of the formidable collective power of the insect race, The white ants of tropical countries sweep away whole villages, with as much certainty as a fire or an inundation; ships even have been destroyed by these indefatigable republics, and the docks and embankments of Europe have been threatened by such minute ravagers.

INSOLVENCY. (See Bankrupt.)

INSTANCE. On the European continent, a court is said to be of the first instance, when it has original jurisdiction of a case; of the second instance, when it has appellate jurisdiction from a lower court; of the third instance, when it has appellate jurisdiction from courts of the second instance. In some cases, generally criminal, a court may be of the first or second instance, according to the place where the process was begun; for instance, if a man is tried in Prussia for a high crime, and found guilty, he appeals, and the case is sent to another criminal court, chosen by the government, which, in this case, is of the second instance; while, in the next case, perhaps, the situation of the two courts may be reversed. To absolve ab instantia means to absolve a person from an accusation, without carrying through the process.

INSTINCT (from the Latin instinctus); that impulse, produced by the peculiar nature of an animal, which prompts it to do certain things, without being directed, in acting thus, by reflection, and which is immediately connected with its own individual preservation, or with that of its kind. Thus the new-born duck hastens to the water, the infant sucks, without being taught to do so; all animals eat when they feel hunger, drink when they are thirsty, by instinct. All the instincts of animals are directed to the preservation either of the individual or of the genus. They appear in the selection of food, avoiding of injurious substances, taking care of their young, and providing for them before they are born; as the bird, for instance, builds its nest to receive its future progeny. The instinct of motion, and the opposite instinct, which compels

the bird, for instance, to remain on her eggs, at the period of incubation, are equally strong. The building of dwellings is, in the case of many animals, a highly curious exercise of instinct; as, for instance, in the case of the beaver and the bee. They are evidently actuated by instinct, as they always succeed the first time they attempt it. Certain instincts lead to certain changes; for instance, to migrating, or to coupling at certain times, to building nests, and expelling the young when they are fledged, and able to take care of themselves. Instinct sometimes misleads; as, for instance, the fly lays its eggs in the flower of the stapelia hirsuta, deceived by the smell of this plant, which resembles that of meat in a state of putrefaction. The young, in this case, perish from want of food. Two things are worthy to be remarked. Men often act from instinct, when least aware of it, and often explain actions in other animals, by instinct, in which they cannot be actuated by it, but in which memory, and the power of combination, must necessarily be supposed. Numberless anecdotes of dogs prove this. The intelligence of animals is an extremely interesting subject, and though there are several highly valuable works on it, yet it is far from having been thoroughly investigated.

INSTITUTE, THE NATIONAL. This learned body, which was organized after the first storm of the revolution, during which all the academies of learning and arts in France had perished, was formed by the decree of the 3d Brumaire of the year 4, from the Académie Française, the Académie des Sciences, and the Académie des Belles Lettres et Inscriptions. Its object was the advancement of the arts and sciences by continual researches, by the publication of new discoveries, and by a correspondence with the most distinguished scholars of all countries, and especially by promoting such scientific and literary undertakings as would tend to the national welfare and glory. The institute was composed of a number of members residing at Paris, and an equal number of associates (associés) in the different parts of the republic. Each class could also choose eight learned foreigners as associates. It was at first divided into three classes, each of which was subdivided into several sections. The first class embraced the physical and mathematical sciences, the second the moral and historical, and the third literature and the fine arts. The number of active members, exclusive of the associés, was limited to 144. The

ex

national institute received, however, its final organization by a decree of the 3d Pluviose of the year 11 (January 23, 1803). It was then divided into 4 classes 1. the class of the physical and mathematical sciences, consisting of 65 members; 2. the class of the French language and literature, consisting of 40 members; 3. the class of history and ancient literature, of 40 members; and 4. the class of the fine arts, with 28 members. In the last years of the imperial government, the title of the national institute was changed for that of the imperial institute. The restoration of the Bourbons gave rise to new changes in this learned body, which restored it, in some degree, to its original condition. A royal ordinance of March 21, 1816, first restored the former names of the classes, so that the name of institute was applied only to the whole body collectively. The same ordinance assigned the first rank to the Académie Française, as being the oldest; the next rank to the Académie des Inscriptions et Belles Lettres ; the third to the Académie des Sciences; and the last to the Académie des Beaux Arts. These united academies were under the personal direction of the king, and each had an independent organization, and a free exercise of the powers committed to them. To each academy were attached 10 honorary members, who had merely the right of being present at the meetings. Such of the former honorary members and academicians as had returned with the court, became, as a matter of right, honorary members of their respective academies. A list of names, appended to the royal decree, determined the members. The Académie Française is well known to be charged with the composition of a French dictionary. Villemain, the successor of Fontanes, and Cuvier, are the most eloquent members. As every one who has brought a vaudeville on the stage with success, thinks himself entitled to a place among the 40 members of this class, these places afford the most fruitful subjects for squibs and satire. The Académie des Inscriptions et Belles Lettres has lately limited its members to 30. It has always been considered a great mark of distinction to be an associé étranger of this class. The number of corresponding members is unlimited. The most distinguished scholars, both in and out of Europe, are thus connected with the society. Committees of this academy superintend the erection of public monuments, and the preservation and description of those already

in existence. Sacy, Daunou, Caussin, Letronne, Boissonade, were chosen from this academy to continue the Notices et Extraits des Manuscripts, de la Bibl. du Roy. The editing of the Journal des Savans, to which the members of all the academies contribute, devolves principally on this academy. They have the distribution of prizes of considerable value. The Académie des Sciences is divided, as formerly, into the two principal departments of the physical and mathematical sciences, and retains most of its earlier regulations, made in the time of the republic. The number of its associés étrangers is limited to 10. Cuvier is perpetual secretary of the physical branch, Fourier of the mathematical. The two secretaries are not confined to a particular section; they belong to all. The Académie des Beaux Arts has five sections. A committee of this academy is charged with the publication of a dictionary of the fine arts. The annual changes which take place in the academies may be learned from the calendar called Institut Royal de France, published by Firmin Didot, printer to the institute.

INSTITUTIONES. and Civil Law.)

(See Corpus Juris,

INSTRUMENT, in music; any sonorous body, artificially constructed for the production of musical sound. Musical instruments are divided into three kindswind instruments, stringed instruments, and instruments of percussion. Of the

stringed instruments among the ancients, the most known are the lyre, psalterium, trigonium, simmicium, epandoron, &c. The principal wind instruments were the tibia, fistula, tuba, cornu, and lituus; those of percussion, the tympanum, cymbalum, crepitaculum, tintinabulum, and crotalum. INSTRUMENTAL MUSIC; music produced by instruments, as contradistinguished from vocal music. The term instrumental is particularly applied to the greater compositions, in which the human voice has no part. The first instrument invented was probably the pipe or flute. An idle shepherd might very naturally, from accident, or in imitation of the effects of the wind, blow through a simple reed, and thus invent the pipe, from which the flute would readily originate. The pipe is, in fact, found among many savages. The invention of stringed instruments, as they are more artificial, is of later origin. The instrumental music of the Greeks was confined to a few instruments, among which the flute, the cithara, the sackbut, though not precisely like those instruments

among the moderns, were the most important. The violin was invented in the middle ages, and soon became the principal instrument, taking place above the flute, though the latter is of much more ancient origin, because the playing on a stringed instrument is less fatiguing, and the tone of the violin is more distinct from the human voice, and, therefore, better fitted to be used with it; besides, the instrument permits much more perfect execution. Until the middle of the last century, the Italian composers used no other instruments in their great pieces, than violins and bass-viols; at that time, however, they began to use the hautboy and the horn; but the flute has never been much esteemed in Italy, particularly in music exclusively instrumental. These were the only wind instruments in Italy, used in instrumental music, until the end of the last century; and even to this day, the Italians use wind instruments much less than the Germans, and particularly the French. Since Mozart, every instrument has been used, which appeared adapted to answer a particular purpose. This is the cause of the fewness of the notes in the Italian, and of their great number in German, and their excess in the modern French scores. In general, symphonies and overtures, solos, duets, terzettos, quartettos, quintettos, &c., sonatas, fantasias, concerts for single instruments,dances, marches, &c., belong to instrumental music.

INSURANCE is a contract, whereby, for a stipulated consideration, called a premium, one party undertakes to indemnify another against certain risks. The party undertaking to make the indemnity is called the insurer or underwriter, and the one to be indemnified, the assured or insured. The instrument, by which the contract is made, is denominated a policy; the events or causes of loss insured against, risks or perils; and the thing insured, the subject or insurable interest. Marine insurance relates to property and risks at sea; insurance of property on shore against fire, is called fire insurance; and the written contracts, in such cases, are often denominated fire policies. Policies on lives are another description of this contract, whereby a party, for a certain premium, agrees to pay a certain sum, if a person, to whose life it relates, shall die within a time specified. These policies, however, usually make an exception of death by suicide. There was a kind of insurance in use, among the Greeks and Romans, called bottomry or respondentia,