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lent friction have the (kin very delicate and tender. Some have sevetal fkn s one above anoi her nearly like the different coats of an onion. The skin of man. and that of the other animals is filled with an infinity of small pores; it resembles a sieve or very fine net, the pores answering to the meshes. By these pores transude a quantity of superfluous humours which are thrown off by sensible or insensible perir.ition. The skin of insects has likewise pores r the fame u(e, and so small, that they are with difficulty seen. As some animals change their hair .ind even their skin every year, experience shews us that infects do the fame. Some throw it off but once ayear, others four times.
Insects which creep into holes, or fissures, where they are exposed to pretty violent rubbing, have their skin harder than others: and even some have it fortified with scales. It likewise serves to defend insects from the injuries of the weather; it is of the fume use to them that scales are to serpents and fishes, sht Its to crabs or shell filh, feathers to birds, and hair to the most of quadrupeds. As insects in general are but small, the heat of the Sun would loon dry up the internal humidity of their bodies, and exhaust their animal spirits, were not they enveloped in a hard skin, which prevents that inconvenience. It is the instrument of motion ro those that want feet ; by extending and contracting it alternately, they transport themlelves from place to place.
Lastly, the skin of insects may be considered as a coat of mail with which God has armed them as a protection from external danger. "Thou hast cloath"ed me with skin," fays Job, Chap. X. ii. to express the means which God had employed to unite, connect, and preserve the different parts he was composed 9!. The Deity has been equally attentive to
T insects insecrs, and it is for the fame purpose that he has likewise cioathed them with a skin.
It is so difsicult to distinguish the head of some in. sects that one would be almost tempted to believe they had none. Some have it exceeding small in proportion to their body, others very large. It is not in all of the fame shape; it is round, flat, oval, broad, acuminated or square in difserent insects. In some it is smooth, in others rough, and some have it set with hairs to suit their manner os lise. There is also gre2t diversuv in the situation of the head. In some it is quito distinct, but in others it is not easy to di'oovvi Seme conceal it und. r their back, like '! c.r*ni'c: under their shell, so that it cannot be seen, 'isiou h most have it straight forward, some have it bent down, ar.d some have a triangular mark on their
Winged insects which have seet are surnished with antennæ on their head, above the eyes, though some have them seated on the rostrum, as all the Curcu'.ios, In the anttnnæ there are many articulations that infects may bend them with facility, and the number of the articulations varies with the necessities of the various insects. It is rare to sind caterpillars with antennæ, but there is a brown caterpillar which lives in society that is distinguished by antennæ with three articulations. Those of the musk beetle have four, those of the pediculi of the Peacock, sive; these os the aphides of the cabbage, six; those of the Ichneumons that are bred in the body of the caterpillar with 72 folds, seven; those of some beetles ei^ht. There are insects which have still a greater number of articulations in their antennæ. Such are all the species of Cerambyx which have tenj the earwig eleven ; the Tipula phalænoides has fourteenj and the ichneumon that breeds in the body of the
green green caterpillars whidh curl up the leaves has six* teen \ the antennae of a Phalæna which seeds on the alder has forty articulations, those of the Phalæna Euonymella sifty; and those of another bred on the willow sixty. Lastly in those of some grasshoppers, there are from eighty to an hundred articulations. .
These articulations are not of equal size, and some are longer than others; some are formed of little spherical bodies like a string of beads, more or less distant; these beads are bare in some« but garnished with hairs in others j in general they are so small that they cannot be seen distinctly but with a glass. In some insects they are hemispherical, in others heartlhaped, and lastly some are toothed like a saw.
The extremity of the antennæ in some insects is thickest, forming a knob, the whole somewhat of the sigure of a drum-stick. That knob is sometimes cleft and divided into several branches. The shaft of the antennæ is sometimes smooth, and sometimes fringed. These last are of two sorts, the one having fringes only on the outside, the other on both sides, like the seather of a bird. This is their appearance when seen with the naked eye, but if a magnisier is employed, we sind that each particular silament of the fringe is itself a seather, having a quill and a plume like those of a bird.
The antennæ are seated on small tubercles yb which the insect can bend them in all directions. They are not always carried in the fame way, some infects bearing them straight forwards, others bent, others turned aside, according to their manner of lise.
Antennæ have been given to insects with different views and for different purposes. It appears to have
T 2 been been the principal inten'ion of the Creator that they mould serve instead of hands, as they feel objects with them in order to judpe whether they are uftful or pernicious. When dust has fallen upon the ever of some insects it is with their antennas that they clean them. It is the more necessary that they should be provided with the means of removing this dust as they have no eye brows, and are therefore more exposed to the inconvenience. In this cafe the antennae are of the lame use with our fingers. They like* wife serve insects as the organ of smell, and by them they discern odours both near and at a distance. The males employ them in caressing the females. They are a fort of measuring rod to others, with which they found the depth of the holes they mean to retire to. Lastly, as we have observed above, the antennæ are one of the marks by which the males of many species may be distinguished from the females.
The flructure of the eye in man and other animals demonstrates, in the most incontestible manner, the power and wisdom of him who made it j but, the evidence of these perfections, drawn from the structure of the eye in insects, is not less strong, ft is true that some insects are destitute of the OTgan of fight, but by far the gTeater number are posiest of it. The form of t!:eir eyes is very various; some have the lustre, and almost, the roundness of pearls, some are hemispherical, others spheroidal. They are not alt of the same colour. We see many butterflies with eyes as white as show, those of spiders are quite black, those of some aphides are of the colour of amber, of jasper or vermilion; the brilliancy in the eyes of some of the inuscæ is like that of gold, for wh eh reason ti ey go by the i ame of the golden-eyed iiies; th-se of the sT"tn jjiafshoppers have the colour of an emerald j lastly, the eyes of some have
.'' as as much sire and brilliancy as a diamond exposed to the rays of the sun : these colours, however, fade as« ter the death of the insect, and sometimes totally disappear.
The eyes of insects are generally placed in the forehead, under the antennæ: but this rule is not without exceptions, for some have them behind the antennæ. In some they stand only a littie out from the head, as in the grasshoppers; in some they are so much raised, that one would think them attached to the head, only by an articulation; such are those of the small dragon-flies.
The number of eyes in insects is not uniform; the greater part have two, but there are some that have sive. Besides the two large net-work eyes, a number of insects have three others on the forehead. Spiders have generally eight eyes, but they are not disposed in the same way, in all the species. Those spiders, however, must be excepted, which have long legs, and antennæ resembling the claws of a crab, for they have but two eyes. Those of some insects resemble two hemispheres, elevated on the two sides of the head, consisting of a vast number of small hexagons like the cells of bees. In each of these hexagons are circles like lenses, which are so many eyes, increasing the power of that or^an, to an insinite degree. By this apparatus, these insects enjoy, not only the advantages of sight, but have it probably clearer and more extensive than other animals.— This was, no doubt, necessary, on account of the rapidity of their flight, and to enable them to descry their food, while flying.
The eyes of insects are neither desended by bones, nor furnished with eye-lids to protect them from accidents: but. to make amends for this, the external