three weeks, and then cast off their last covering, the whole insect being, after this, of a bright yellow colour, the wings only excepted; but after this change they become of a deeper yellow, and in a very few hours, of a dark brown, if we except the body, which is something lighter coloured, and has a reddish cast. The males no sooner come to maturity than they copulate with the females, who, in a day or two after their intercourse with the males, lay their eggs, generally near the buds. Where there are a number crowded together, they, of course, interfere with each other, in which case they will frequently deposit their eggs on other parts of the branches.It is highly probable that the aphides derive considerable advantages by living in society; the reiterated punctures of a great number of them may attract a larger quantity of nutricious juices to that part of the tree or plant where they have taken up their abode. The observations of Mr. Curtis on the aphides are chiefly intended to shew that they are the principal cause of blights in plants, and the sole cause of the honey-dew. He therefore calls them the aphis, or blighter; and after observing, that, in point of numbers, the individuals of the several species composing it surpass those of any other genus in the country, speaks thus, in general terms, of the whole tribe. These insects live entirely on vegetables. The loftiest tree is no less liable to their attacks than the most humble plant. They prefer the young shoots on account of their tenderness, and on this principle, often insinuate themselves into the very heart of the plant, and do irreparable mischief before they are discovered. But, for the most part, they beset the foliage, and are always found on the underside of the leaf, which they prefer, not only on account of its being the most tender, but as it affords them protection from the weather, and various injuries to which they would otherwise be exposed. Sometimes the root is the object of their choice, which, from the nature of these insects one would not, à priori, expect; yet I have seen the roots of lettuces thickly be set with them, and the whole crop rendered sickly and of little value; but such instances are rare. They seldom attach themselves to the bark of trees, like the aphis salicis, which being one of our largest species, and hence possessing superior strength, is enabled to penetrate a substance harder than the leaves themselves.

In the quality of the excrement voided by these insects, there is something wonderfully extraordinary. Were a person accidentally to take up a book, in which it is gravely asserted, that in some countries there were certain animals which voided liquid sugar, he would lay it down, regarding it as a fabulous tale, calculated to impose on the credulity of the ignorant; and yet such is literally the truth. Mr. Curtis collected some on a piece of writing-paper, from a brood of the aphis salicis, and found it to be sweet as sugar; and observes, that were it not for the wasps, ants, flies, and other insects that devour it as quickly as it is produced, it might, no doubt, be collected in considerable quantities, and by the processes used with other saccharine juices, might be converted into the choicest sugar or sugar-candy. The sweetness of this excrementitious substance, the glossy appearance it gave the leaves it fell upon, and the swarms of insects this matter attracts, led him to imagine the honey-dew of plants was no other than this secretion, which further observation has since fully confirmed; and not, as its name implies, a sweet substance falling from the atmosphere. On this opinion it is further remarked, that it neither falls from the atmosphere, nor issues from the plant itself, as is easily demonstrated. If it fell from the atmosphere, it would cover every thing it fell upon indiscriminately, whereas we never find it but on certain living plants and trees. We find it also on plants in stoves and green-houses covered with glass. If it exuded from the plant, it would appear on all the leaves generally and uniformly; whereas its appearance is extremely irregular, not alike on any two leaves of the same tree or plant, some having none of it, and others being covered with it but partially. It is probable that there never exists any honeydew but where there are aphides; though such often pass unnoticed, being hidden on the underside of the leaf: and wherever honey-dew is observable upon a leaf, aphides will be found on the underside of the leaf or leaves immediately above it, and under no other circumstance whatever. If by accident any thing should intervene between the aphides and the leaf next beneath them, there will be no honey-dew on that leaf: and thus he conceives it is incontrovertibly proved that aphides are the true and only source of honey-dew. Of the British species of aphides, one of the largest and most remarkable is the aphis salicis,

which is found on the different kinds of willows. When bruised, these insects stain the fingers with red. Towards the end of September multitudes of the full-grown insects of this species, both with and without wings, desert the willows on which they feed, and ramble over every neighbouring object in such numbers that we can handle nothing in their vicinity without crushing some of them, while those in a younger, or less advanced state, still remain in large masses upon the trees. Aphis rosa is very frequent, during the summer months, on the young shoots and buds of roses: it is of a bright green colour: the males are furnished with large transparent wings. A. vitis is most destructive to vines; as A. ulmi is to the elm-tree. Plate I. Entomology, fig. 3.

It is found, that where the saccharine substance has dropped froin aphides for a length of time, as from the aphis salicis in particular, it gives to the surface of the bark, foliage, &c. that sooty kind of appearance which arises from the explosion of gunpowder: it looks like, and is sometimes taken for, a kind of black mildew. In most seasons the natural enemies of the aphides are sufficient to keep them in check, and to prevent them from doing essential injury to plants in the open air: but there are times, once perhaps in four, five, or six years, in which they are multiplied to such an excess that the usual means of diminution fail in preventing them from doing irreparable injury to certain crops.

To prevent the calamities which would infallibly result from an accumulated mul. tiplication of the more prolific animals, it has been ordained by the Author of nature, that such should be diminished by serving as food for others. On this principle, most animals of this kind have one or more natural enemies. The helpless aphis, which is the scourge of the vegetable kingdom, has to contend with many of these, the principal are, the coccinella; the ichneumon aphidum, and the musca aphidevora. The greatest destroyer of the aphides is the coccinella, or common lady-bird. During the winter this insect secures itself under the bark of trees and elsewhere. When the spring expands the foliage of plants, the female deposits its eggs on them in great numbers, from whence, in a short time, proceeds the larva, a small grub, of a dark lead-colour spotted with orange. These may be observed in the summer season running pretty briskly over all kinds of

plants, and if narrowly watched, they will be found to devour the aphides wherever they find them. The same may be observed of the lady-bird in its perfect state. Another most formidable enemy to the aphis is a very minute, black, and slender ichneumon fly, which eats its way out of the aphis, leaving the dry inflated skin of the insect adhering to the leaf like a small pearl: such may always be found where aphides are in plenty. Different species of aphides are infested with different ichneumons. There is scarcely a division of nature, in which the musca or fly is not found: of these, one division, the aphidivora, feeds entirely on aphides Of the different species of aphidivorous flies, which are numerous, having mostly bodies variegated with transverse stripes, their females may be seen hovering over plants infested with aphides, among which they deposit their eggs on the surface of the leaf. The larva, or maggot, produced from such eggs, feeds, as soon as hatched, on the younger kinds of aphis, and as it increases in size, attacks and devours those which are larger. The larva of the hemerobius feeds also on the aphides, and deposits its eggs on the leaves of such plants as are beset with them. The earwig is likewise an enemy to them, especially such as reside in the curled leaves of fruit-trees, and the purses formed by certain aphides on the poplars and other trees. To these may be added the smaller soft-billed birds that feed on insects.

APHORISM, a maxim or principle of a science; or a sentence which comprehends a great deal in a few words. The term is seldom used but in medicine and law. say, the aphorisms of Hippocrates, the aphorisms of the civil law, political aphorisms, &c.

We

APHRODITA, in natural history, a genus of worms, of the order Mollusca. Body creeping, oblong, covered with scales, and furnished with numerous bristly fasciculate feet on each side; mouth terminal, cylindrincal, retractile; feelers two, setaceous, annulate; and four eyes. There are nine species. A. aculeata has an oval body, brown, beneath flesh colour, with long silky changeable hair on each side the body: it in habits the European seas, is found in the belly of the cod-fish, and feeds on testaceous animals; is from four to seven inches long.

APHYLLANTHES, the blue Montpelier pink, in botany, a genus of the Hexandria Monogynia class of plants, the calyx of which is composed of a number of imbri

cated, lanceolated spathæ; the corolla consists of six petals, of an obversely oval figure, terminating at the base in very narrow ungues, and patent at the limb, forming a kind of tube below it: the fruit is a turbinated capsule of a triangular figure, and contains three cells; the seeds are oval. There is but a single specics.

APHYTEIA, in botany, a genus of the Monadelphia Triandria. Calyx large, funnel-form, three cleft; three petals inserted into and shorter than the calyx; germ inferior; berry one-celled, many-seeded; seeds imbedded.

APIAN, (PETER), in biography, an eminent astronomer and mathematician, called in German Bienewitz, was born at Loisnich, in Misnia, and became professor of mathematics at Ingoldstadt, in 1524. He wrote several treatises on astronomy and the mathematics, and enriched these sciences with many instruments and observations. His first work was a "Treatise on Cosmography, or Geographical Instructor:" this was published in 1530, and in three years after he constructed at Nuremberg a curious instrument, which shewed the hour of the day by means of the sun's rays, in all parts of the earth. In the year 1540, he published his principal work entitled "Astronomicon Cæsaræum," containing many interesting observations, with the descriptions and divisions of instruments, calculations of eclipses, and the construction of them in plano. In a second part of the work is a description of the construction and use of an astronomical quadrant, to which is annexed observations on five different comets: in these he shews that the tails of comets are always projected in a direction opposite to the sun. Our limits do not allow us to enumerate all the treatises of Apian: they were as respectable as numerous, and the author was treated with the kindest attention by the emperor Charles V., who published several of his works at his own expense, conferred upon him the honour of nobility, and presented him with 3000 crowns. Apian died at Ingolstadt in 1552, leaving behind him a high reputation for learning, and a son Philip, who was also an eminent astronomer, and taught the sciences both at Tubingen and Ingolstadt. Philip died in 1589, and left a treatise on "Solar-dials." He gave an account of the new star that appeared in Cassiopeia in 1572, which is preserved.

APIARY, a garden or other convenient place where bees are kept. A southern as、pect is reckoned the most proper, and the

bee-hives should be exposed as little as possible to the wind, and should enjoy as much of the influence of the sun as possible, as wind retards the bees in their work, while the beams of the sun invite them to it. In the vicinity of the apiary there should be plenty of flowers, wild thyme, and the like. The hives should be free from the droppings of trees, the annoyance of dunghills, long grass and weeds; as from these, insects are bred, which are not only destructive to bees, but greatly retard them in the preparation of honey. See APIs.

APIS, in natural history, a genus of insects of the order of Neuroptera. Gen. char. mouth furnished with jaws, and an inflected proboscis, with two bivalve sheaths; wings flat or without plaits; sting in the female and neutral insects concealed.

This genus is distributed by Linnæus into two assortments, viz. those in which the body of the animal is but slightly covered with fine hair or down, and those in which it is remarkably villose or hairy: the insects of the latter division are commonly distinguished by the title of humble-bees. In the first division, the principal or most important species is the apis mellifica, or common honey-bee, so long and justly celebrated for its wonderful polity, the neatness and pre-` cision with which it constructs its cells, and the diligence with which it provides, during the warmth of summer, a supply of food for the support of the hive during the rigours of the succeeding winter. The general history of this interesting insect has been amply detailed by various authors, as Swammerdam, Reaumur, &c. &c. Among the most elaborate accounts of later times, may bé mentioned that of Mr. John Hunter, which made its appearance in the Philosophical Transactions for the year 1792, of which the following is an abstract. There are three periods at which the history of the bee may commence: first, in the spring, when the queen begins to lay her eggs; in the summer, at the commencement of a new colony; or in the autumn, when they go into winter quarters. We shall begin the particular history of the bee with the new colony, when nothing is formed. When a hive sends off a colony, it is commonly in the month of June; but that will vary according to the season, for in a mild spring bees sometimes swarm in the middle of May, and very often at the latter end of it. Before they come off, they commonly hang about the mouth of the hole or door of the hive, for some days, as if they had not sufficient room with

in for such hot weather, which we believe is very much the case; for if cold or wet weather come on they stow themselves very well, and wait for fine weather. But swarming appears to be rather an operation arising from necessity, for they would seem not naturally to swarm, because if they have an empty space to fill they do not swarm; therefore by increasing the size of the hive the swarming is prevented. This period is much longer in some than in others. For some evenings before they come off is often heard a singular noise, a kind of ring, or sound of a small trumpet; by comparing it with the notes of the piano-forte, it seemed to be the same sound with the lower A of the treble. The swarm commonly consists of three classes; a female or females, males, and those commonly called mules, which are supposed to be of no sex, and are the labourers; the whole, about two quarts in bulk, making about six or seven thousand. It is a question that cannot easily be determined whether this old stock sends off entirely young of the same season, and whether the whole of their young ones, or only part. As the males are entirely bred in the same season, part go off; but part must stay, and most probably it is so with the others. They commonly come off in the heat of the day, often immediately after a shower. When one goes off they all immediately follow, and fly about seemingly in great confusion, although there is one principle actuating the whole. They soon appear to be directed to some fixed place; such as the branch of a tree or bush, the cavities of old trees, holes of houses leading into some hollow place; and whenever the stand is made, they immediately repair to it till they are all collected. But it would seem, in some cases, that they had not fixed upon any resting place before they come off, or, if they had, that they were either disturbed, if it was near, or that it was at a great distance; for, after hovering some time, as if undeter mined, they fly away, mount up into the air, and go off with great velocity. When they have fixed upon their future habitation, they immediately begin to make their combs, for they have the materials within themselves. "I have reason," says Mr. Hunter, "to believe that they fill their crops with honey when they come away, probably from the stock in the hive. I killed several of those that came away, and found their crops full, while those that remained in the hive had their crops not near so full: some of them came away with farina on their legs,

which I conceive to be rather accidental; I may just observe here, that a hive commonly sends off two, sometimes three swarms in a summer, but that the second is commonly less than the first, and the third less than the second; and this last has seldom time to provide for the winter.

"The materials of their dwelling or comb, which is the wax, is the next consideration, with the mode of forming, preparing, or disposing of it. In giving a totally new account of the wax, I shall first shew it can hardly be what it has been supposed to be. First, I shall observe that the materials, as they are found composing the comb, are not to be found in the same state (as a composition) in any vegetable, where they have been supposed to be got. The substance brought in on the legs, which is the farina of the flowers of plants, is, in common, I believe, imagined to be the materials of which the wax is made, for it is called by most the wax: but it is the farina, for it is always of the same colour as the farina of the flower where they are gathering; and, indeed, we see them gathering it, and we also see them covered almost all over with it like a dust; nevertheless, it has been supposed to be the wax, or that the wax was extracted from it. Reaumur is of this opinion. I made several experiments to see if there was such a quantity of oil in it, as would account for the quantity of wax to be formed, and to learn if it was composed of oil. I held it near the candle, it burnt, but did not smell like wax, and had the same smell, when burning, as farina when it was burnt. I observed that this substance was of different colours on different bees, but always of the same colour on both legs of the same bee; whereas a new made comb was all of one colour. I observed that it was gathered with more avidity for old hives, where the comb is complete, than for those hives where it only begun, which we could hardly conceive if it was the materials of wax: also we may observe that at the very beginning of a hive, the bees seldom bring in any substance on their legs for two or three days, and after that the farina gatherers begin to increase; for now some cells are formed to hold it as a store, and some eggs are laid, which when hatched will require this substance as food, and which will be ready when the weather is wet.

"The wax is formed by the bees themselves; it may be called an external secretion of oil, and I have found that it is formed between each scale of the under side of the

belly. When I first observed this substance, in my examination of the working bee, I was at a loss to say what it was: I asked myself if it was new scales forming, and whether they cast the old, as the lobster, &c. does? but it was to be found only between the scales on the lower side of the belly. On examining the bees through glass hives, while they were climbing up the glass, I could see that most of them had this substance, for it looked as if the lower, or posterior edge of the scale, was double, or that there were double scales: but I perceived it was loose, not attached. Finding that the substance brought in on their legs was farina, intended, as appeared from every circumstance, to be the food of the maggot, and not to make wax; and not having yet perceived any thing that could give me the least idea of wax, I conceived these scales might be it, at least I thought it necessary to investigate them. I therefore took several on the point of a needle, and held them to a candle, where they melted, and immediately formed themselves into round globules; upon which I no longer doubted but this was the wax, which opinion was confirmed to me by not finding those scales but in the building season.

"The cells, or rather the congeries of cells, which compose the comb, may be said to form perpendicular plates, or partitions, which extend from top to bottom of the cavity in which they build them, and from side to side. They always begin at the top or roof of the vault, in which they build, and work downwards; but if the upper part of this vault to which their combs are fixed, is removed, and a dome is put over, they begin at the upper edge of the old comb, and work up into the new cavity at the top. They generally may be guided as to the direction of their new plates of comb, by forming ridges at top, to which they begin to attach their comb. In a long hive, if these ridges are longitudinal, their plates of comb will be longitudinal; if placed transverse, so will be the plates; and if oblique, the plates of comb will be oblique. Each plate consists of a double set of cells, whose bottoms form the partition between each set. The plates themselves are not very regularly arranged, not forming a regular plane where they might have done so; but are often adapted to the situation or shape of the cavity in which they are built. The bees do not endeavour to shape their cavity to their work, as the wasps do, nor are the cells of equal depths, also fitting them to

their situation; but as the breeding cells must all be of a given depth, they reserve a sufficient number for breeding in, and they put the honey into the others, as also into the shallow ones. The attachment of the comb round the cavity is not continued, but interrupted, so as to form passages; there are also passages in the middle of the plates, especially if there be a cross stick to support the comb; these allow of bees to go across from plate to plate. The substance which they use for attaching their combs to surrounding parts, is not the same as the common wax; it is softer and tougher, a good deal like the substance with which they cover in their chrysalis, or the humblebee surrounds her eggs. It is probably a mixture of wax with farina. The cells are placed nearly horizontally, but not exactly so; the mouth raised a little, which probably may be to retain the honey the better; however, this rule is not strictly observed, for often they are horizontal, and towards the lower edge of a plane of comb they are often declining. The first combs that a hive forms are the smallest, and much neater than the last, or lowermost. Their sides or partitions, between cell and cell, are much thinner, and the hexagon is much more perfect. The wax is purer, being probably little else but wax, and it is more brittle. The lower combs are considerably larger, and contain much more wax, or perhaps, more properly, more materials; and the cells are at such distances as to allow them to be of a round figure: the wax-is softer, and there is something mixed with it. I have observed that the cells are not all of equal size, some being a degree larger than the others; and that the small are the first formed, and of course at the upper part, where the bees begin, and the larger are nearer the lower part of the comb, or last made: however, in hives of particular construction, where the bees may begin to work at one end, and can work both down and towards the other end, we often find the larger cells both on the lower part of the combs, and also at the opposite end. These are formed for the males to be bred in; and in the hornets and wasps combs there are larger cells for the queens to be bred in: these are also formed in the lower tier, and the last formed.

"The first comb made in a hive is all of one colour, viz. almost white; but is not so white towards the end of the season, having then more of a yellow cast.

"There is a cell which is called the royal