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a rudder to fteer them. Others, which are fhortfighted, use them for exploring the road, both before and behind them. Some employ them in cleaning their eyes, their antennæ, and their wings, and in clearing them of the duft and earth which might incommode them. Thofe which dig in the earth, use their legs as pick-axes, to make cavities and fubterraneous paffages. As men ufe their arms, and fome animals their feet, as weapons of defence, there are infects which make the fame ufe of theirs. I believe I have already mentioned that fome ufe them for feizing and holding their prey. Lastly, by the ftruc. ture of the legs, the fpecies of infects are often di ftinguishable.

The wings are the principal things to be noticed in winged infects. I have already spoken above of the number which the different kinds of infects poffefs; and have obferved, that fome have two, others four. They are fo delicate, and their ftructure difcovers fo much art, that they may well pafs for one of those objects that moft clearly demonftrate the wifdom of the Creator. They are provided with different nerves, which, like those of leaves, are diftributed in different directions. The pofition of them is alfo different, in different infects. In fome they are horizontal, in others they decline a little towards the fides, and in others, they ftand erect. The remarks which I have had occafion to make in fome of the preceding articles, fufficiently fhew, that the wings of infects are very various. Some have a kind of a covering over them, while others are bare. Some of thefe laft are exceedingly thin, fhining, and tranfparrent, like parchment or fine gauze; others are opaque, and covered with a fort of farina or powder. I have also already examined the different forts of butterflies and winged beetles, fo that I have only here to treat of the wings themselves..

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The wings of infects, which are bare, whether they have two or four, are exceedingly thin, and their nerves are ramified in different directions. In fome, these ramifications extend from the body to the half of the wings only, where they are loft and disappear, as in the Hippobofca equina. In others they reach the margin of the wings, where they join and form a spot, which Frifch calls the marginal Ipot, as in the Hemerobius Chryfops. Thefe ramifications affume various figures. Sometimes they are fquares, which, at the fuperior extremity divide into three branches, as in fome Libellulas, in others they are rhomboidical, as in the grafshoppers, pentagonal, or irregularly pentagonal, as in the Sphex fabulofa: the membrane that fills up the interftices of these nerves is fo thin, that it can hardly be perceived, and the whole wing appears like thin gauze.

There is great diverfity in the figure of the farinaceous wings. They may be compared to the leaves of different trees; whatever connection there may be among them, there is not one of them like another. They are round, long, heart-shaped, indented, or intire in the margins, oval, or nearly oval, their ends ferminating in a point; in others they form triangles, the ends being either pointed or rounded. The margin of the wings is often indented like the edge of a faw, or undulated, forming femicircles like the figure of a ferpent in motion; and fometimes be tween these circles there are fmall elevations. Some at the extremity of the wings have a fort of tail, like that of a fwallow, fome have it ornamented with fine fringes like lace.

When the duft which covers the wings of infects is looked at with the naked eye, one would take it for nothing but fine farina or powder; but, if it is fsen through a magnifier, this pretended duft appears

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in the form of very delicate feathers, which easily come off on being touched. The fmall feathers are of very different figures; fome have the form of a a battledore with a fhort handle, others are almost pval, except at the bafe, where they are a little notched; fome are like the leaves of a willow, except that they are fometimes indented at top: fome refemble a fan, a fquare with rounded angles, but waved at top; others are pointed at the bafe, and enlarge gradually, terminating in two, three, four, and even five long points like a finger; fome refemble the heart-shaped leaves of trees, and terminate in two or three hooked points; others are oblong, and pointed at their origin, where they are oval, and have at the extremity, three, four, and even a greater number of fhort points; laftly, fome are long, thickening at the base, flender in the middle, and are twice as broad at the top, as at the bottom.

Without taking into account, the different colours of thefe wings, of which we fhall hereafter take notice, many are marked with fingular characters. On the wings of fome, are marks which refemble Hebrew letters, on others a Roman C, a Greek upfilon, a V, or an O. Madame Merian obferved, on the wings of a butter: fly, characters refembling the letters BCY M; this i have not myfelf feen. Others are marked with a St Andrew's crofs, and fome with the figure of an arrow.

The wings that have cafes are not lefs worthy of attention than the others; thefe cafes are hard as horn, and are eafily broken. They are like a fheath to the delicate wings, which they cover and preferve from injury. As infects have no bones, thefe ferve inftead of them externally. They are not of equal hardness in all infects, the genus of Cantharis has them thin and flexible, and Frifch fays of the Cantha

ris fufca, that when it dies, the elytra fhrivel up. There is likewife great diverfity in their length; in fome, they cover only a fmall part of the body below the thorax, in others they cover the halt of it; in fome they hardly reach the extremity of the abdomen, in others they cover the whole of it. Sometimes thefe cafes are nearly opaque, and hard as horn; in others thin and nearly tranfparent. Not lefs variety is obfervable in their fhape. Some, when joined together, are round, like the fection of a fphere, others oval, oblong, or ftraight. Some are exceedingly smooth and polifhed, others have a border, or are dotted with little depreffions, as if made with a pin. Some have longitudinal lines like the furrows of a ploughed field, and others are fet with hairs, or adorned with little tubercles, covering the furface.

The wings to which these cafes ferve as covers are very fine and tranfparent. In fome fpecies they are not longer than the cafes themselves and may be covered therefore without being folded. But there are others which have them much longer, and must fold them up when they are not flying to put them under the elytra. For this purpose they have at the external margin an articulation or a kind of fpring to fold up what is longer than the cafes. When thefe wings are laid on the back, their largest nerves are without fupport, and the two ends which are too long hang down. But when the elytra are laid down to cover them, they lower at the fame time thefe nerves, and then the two ends drawn by their mufcles are folded in, and take their proper place. In order to accomplish this, the beetle has nothing to do but to leave a small space between the elytra and abdomen that what remains of the wing may the more eafily be folded: and this happens with all X 2

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thofe cruftaceous infects, whofe wings are longer than the elytra.

Many fpecies of infects are covered with hairs; fometimes these are so fine that they escape the naked eye, and are visible only with a good glafs. But in others they are fufficiently obvious. They do not cover the whole body: fome have them on the head where they look like a plume of feathers, fome on the thorax, on the extremity of the abdomen, on the wings, both upper and under, and on the legs.

Thefe hairs are of different colours which change however when the infects grow old, and are about to form their cone. They are thinly scattered on fome, on others thickly fet. There are alfo infects where the hairs form tufts, like a brush, (fafciculi) as in the Phalana pudibunda; fome fquare, others round, often equal at top as if cut over like the egrets in the turban of a Turk, and often terminating in a point like a pencil. Sometimes the hairs are fo grofs and ftrong that they may juftly be called fpines; each of these spines fometimes dividing into many rigid branches, and fo fmall as to be with difficulty feen. They too are of different colours, as may be feen in the different fpecies of the thorny caterpillars and the number of their branches varies, fome having three, four or more. Their pofition is also very different. In fome the spines are placed round each ring in one line as in the caterpillar of the Papilio Io; in others they are placed in two lines, not oppofite to one another but alternate, and always at fuch equal diftances, that one would fay they had been measured with the greatest care; an inftance of this may be feen in the caterpillar of the Papilio Urtica.

These hairs and fpines answer more than one purpose. They preferve fome from two great friction

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