as much fire and brilliancy as a diamond expofed to the rays of the fun thefe colours, however, fade after the death of the infect, and fometimes totally difappear.

The eyes of infects are generally placed in the forehead, under the antennæ: but this rule is not without exceptions, for fome have them behind the antennæ. In fome they stand only a little out from the head, as in the grafshoppers; in fome they are so much raised, that one would think them attached to the head, only by an articulation; fuch are thofe of the fmall dragon-flies.

The number of eyes in infects is not uniform the greater part have two, but there are fome that have five. Befides the two large net-work eyes, a number of infects have three others on the forehead. Spiders have generally eight eyes, but they are not disposed in the fame way, in all the fpecies. Thofe fpiders, however, must be excepted, which have long legs, and antennæ refembling the claws of a crab, for they have but two eyes. Thofe of fome infects resemble two hemifpheres, elevated on the two fides of the head, confifting of a vast number of small hexagons like the cells of bees. In each of these hexagons are circles like lenfes, which are so many. eyes, increafing the power of that organ, to an infinite degree. By this apparatus, thefe infects enjoy, not only the advantages of fight, but have it probab ly clearer and more extenfive than other animals.This was, no doubt, neceffary, on account of the rapidity of their flight, and to enable them to defcry their food, while flying.

The eyes of infects are neither defended by bones, nor furnished with eyelids to protect them from accidents but to make amends for this, the external

coat

i.

coat is fo hard, as to fecure them from the dangers they would otherwife have to dread. I imagine, that the hemifpherical figure of the cornea anfwers the purposes of the cryftalline and other humours; and I believe that, in place of the different coats of the eye, each hexagon receives a particular branch of the optic nerve. The eyes of other animals are moveable, but those of infects, are for the most part fixed.

There is great art, and many things remarkable in the structure of the mouth in infects. There is almoft as much diverfity in the figure of this organ, as there are different fpecies. It is broad, pointed, or long like the fnout of a pig; and this laft of various lengths and shapes.

Many infects have a fort of lips, not only on the upper and under fide of the mouth, but at the fides. A great number have palpi at the mouth, by which they examine their food, and with which they introduce it, and they likewise use them for cleaning it. These palpi have several articulations, fome have two, three, four, five, and even more. Some infects have only two palpi, others four. The extremity of them is often round and clubbed. It is channelled in fome beetles, and oblong in others.

We find alfo, in the mouth of infects, a fort of jaws or pincers, (mandibula,) which ferve instead of teeth. These they use in comminuting their food, or in breaking other fubftances. But, though these inftruments are exceedingly fine and delicate, they are at the fame time very hard and ftrong. They are fo fharp that fome can pierce the hardest wood, and make holes for themfelves to live in. Thofe who live only on foft fubftances, have no ufe for teeth fo hard or fo fharp; accordingly, they are obferved to be blunt in fome beetles that live on rotten

wood,

wood, Thefe pincers, in fome infects, are exceedingly smooth and fhining; they pretty much refemble the fpur of a cock, as may be feen in the larva of the Hemerobius. Some have fmall teeth on the fide of thofe parts which form the pincers, and oppofite to one another. They are not broad like thole in man, but pointed and curved, nearly like the teeth of a faw. Their number is not equal. Beetles have two; Scolopendra three, and the larvæ of dragon, flies fix. The maxillæ of fome infects have at their base two singular knobs, with a longitudinal recess, into which the maxillæ can be folded, like the blade of a clafp-knife. When the infect would feize any thing, and for that purpose joins the two pieces of these pincers, they do not touch, in fome infects, except at the points; in others, which have them long, er, they fold over each other.

These pincers are of great ufe to them; ferving them not only instead of teeth, in breaking and comminuting the food they take, but for grinding many other substances, according to their neceffities. It is with these they seize their prey, and hold it fast, They are likewife arms both offenfive and defenfive. Thofe which make holes in the ground, employ them in removing the things that obftruct their progrefs.

There are fome infects of prey, (for they well deferve the name,) which, befides thefe pincers, have, at the mouth a fort of claws, with which they hold their booty, as birds of prey hold theirs with their feet. Others likewife have jaws (maxilla) fituated under the pincers, which are moveable, like them, but in a lefs degree.

I must not in filence pafs over the trunk, or, as others call it, the tongue of infects. Some, as the grafshoppers, carry it between their pincers. There

are

are fome that can extend and draw it in at pleasure The Lepidoptera roll it up very adroitly, between two bearded bodies that conceal and protect it: others place it along their abdomen, where there is a little furrow formed for its reception. This trunk is not always of equal length: fome have it very fhort, and fome longer than the whole body. When it is viewed through a microscope, it is found to be very curiously fabricated, and, in a manner, adapted to the way of life of the particular infect; All its parts are fo difpofed, that nothing is fuperfluous, nothing deficient. In fome, it is inclofed in a fort of sheath, which terminates in a very acute point, ferving to pierce the substances that contain their food. When they have done this, they open the sheath, and infert the trunk into the wound, that they may extract the juice. It ferves, therefore, as a syphon to fuck the fluids they ufe as aliment. And befides this, it

ferves to prick, and to wound like a lancet. Though this trunk is so small that it can hardly be perceived, except it be with a glafs, it is, neverthelefs, fo hard, that it can pierce, without difficulty, the hardest and thickeft hide.

After the head, there follows the neck, the thorax and lastly the abdomen. The thorax is more or less hard in proportion as the habits of the infect expose it to a greater or lefs degree of attrition. Thofe

which creep into clefts as the Cimices, have this part of the body fomething flat, that they may the more eafily penetrate. It is more rounded in others, and fome, like the Silphas, have it furnished with elevated margins, occafioning a pretty confiderable corref ponding furrow. The thorax in fome terminates in a point behind, and that of others is blunt or rounded, as in grafshoppers. Many have it fet with hairs, and others with minute elevations which defend it from the effects of violent friction. It is furmount

ed

ed in fome with a protuberance, with two angles, with a horn, or with bodies of a pyramidical or rhomboidal figure."

In 'the abdomen of infects there are many things which merit attention; and in "the first place those incifures from which these animals derive their name. These are called rings or articulations; they are formed with great art, and very much differ in appearance. Some are very clofe, and look like wrinkles, others are broad and long: fome are square and fome are furnished with a margin or rim; and often there is an opening difcoverable between the folds. All infects, as may be eafily imagined, have not the fame number of these rings. Some have five, some fix, and fome feven; all caterpillars havė ten, and the aphides of the cabbage twelve. Some Scolopendræ have twenty, fome forty or fifty, and a certain larva of a Tenthredo feventy-two.

It

Thefe rings are of effential ufe to infects. is by extending and contracting these that they move. By contracting them they defend the delicate parts of their internal frame from the heat of the Sun, from rain and from wind. If they need heat or refreshment, they can procure either the one or the other by the dilatation of their rings which then allow a free paffage to the rays of the Sun, or the fresh air. As they can dilate themselves at pleasure they can receive the precife quantity of either they have occafion for.

There is fuch diverfity of figure in the bodies of infects and they are fo wonderfully formed that an exact defcription of them would be impoffible. The body of fome, as the fpider, is of a spherical fhape, that of others as the cocinella, is hemifpherical. Some are round and flat, as the pediculi of the bat, others U

are