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which could not but injure their skin; they are like. wise weapons of offence, others striking their enemies with them very forcibly. Lastly, in those that live un. der water, there are some that encompass their hairs with a bubble of air which serves them to come up more easily to the surface. The water beetles have hairs on the belly between which there are little par. ticles of air. When these are numerous they des fcend to the bottom with difficulty, and when they reach it, they are obliged to hold by some substance to keep themselves there: but when they loose their hold, the air carries them up to the surface.
Nature has endowed some insects with horns dif, ferent from the aniennæ, having no articulations. Some have but one placed on the head, and rising straight or recurved like a hook. Some have two placed on the forehead bending to the sides or rising in a straight line. These horns are either short, smooth, or a little incurved like hooks, or branched like those of the flying stag. Sometimes they are of equal length, fometimes one is longer than the other. There are likewise insects which have three of these horns rising perpendicularly. They are not always fituated on the head, but sometimes on the shoulders near the head. Lastly, in some insects they are im. moveable, but moveable in others. These last can by their means hold their prey as with pincers, and the former can remove any obstacle from their way,
:CH A P. II.
CH A P. II.
OF THỊ INTERNAL PARTS OF INSECTS,
Let us now come to the internal parts of insects, and letfus fcrutinize the inmost recesses of their structure in order to penetrate into the mysteries of nature. The task is full of difficulty. Many of those parts are so small as to escape our fight. To discover them we must use the highest magnifiers. Besides, the eye is weakened by the continued contemplation of one object, and we feel this sensibly when we force ourselves to the task. Notwithstanding these dif. ficulties, however, Naturalists have discovered many things on our present fubject; these I`shall detail, and add what I have learnt from my own obser. vations.
If we separate the external skin from an insect with instruments, or throw it into warm water, that the skin may come away of itself, we shall find that it co. vers many parts worthy of attention. And first in the head we discern the brain, the substance of which is so soft' that it is not easily examined even with a
glass. When we pierce the eyes of ipfects with a pin . there issues out a fluid, in some clear like water, in
others red like blood. Under the skin is the flesh. It may well receive the name since it consists of fib.
fous parts soft and sometimes reddish as in other a. nimals. The fibres are oblong parts, thin and slender like the finest thread ; their use is to connect the other parts with one anotber, and to put them in motion. They resemble wrinkles in the form of rings, and are distinctly observable in insects when the mula cles are inactive; but when these are in motion they stretch the fibres, and make them invisible. The excessive delicacy of the fibres in insects has prevented hitherto our discovering whether they are enveloped with a fine membrane, like those of quadrupeds. In some insects these fibres are fo short that their length is hardly equal to the breadth of three hairs; and therefore, they are not always to be seen, even with a glass. As they serve to extend, and to contract the muscles, their structure must resemble that of a wire wound round a cylinder, when that cylinder is withdrawn. They vary their motion, folding them. felves in a semi-circle, sometimes to the right, some. times to the left, nearly like a number of small worms. This motion, however, is very inconfiderable, and the fibres hardly change their situation. After these, the flesh of infects appears, as in other animals. There are likewise finall veins, which, joined to the nervous and flcthy fibres, compose the muscles,
Insects are destitute of blood, properly so called ; because, the composition of that fubitance demands more preparation and elaboration than can be perfor. med in a body to small as theirs z. but, in place of blood, they have certain viscid humours that serve the purposes of it. These humours contain their animai fpiriis, and from them insects draw their nou. rilhment. However subtile they may be, they are, nevertheless, endowed with considerable tenaciry. In i consequence of this quality, the head of a fly, after being cut off, will adhere again to its body, if stuck
on, without, however, restoring it to life. This glus tinous quality of the humours enables insects to live for a time, after having been cut into two or more pieces; it prevents a rapid evaporation, it retains the humours which still continue to circulate for a time in the members, which would not happen without this quality. And, that this quality actually resides in the humours of insects, we may be convinced, by exposing them, when drawn from the animal, to the air, when they will so dry, in a few minutes, as to become brittle like glue.
Insects have an artery, which is observable, runing along their back, and in which pulsation may be seen. The air produces in this artery the fame effect that blood does in circulation.
Insects eat and drink like other animals, a stomach is therefore necessary to them. This is nothing but an extremely thin and hollow bag. The aliments of insects pass from the gullet into this stomach, where they are digested and changed into a nutritive juice. Among quadrupeds, those that ruminate need more than one Itomach, formed of several folds. It is the same with infects ; some of them are found to rumi. nate, and consequently, have more than one stomach. It is of this sort of infe&ts that God permitted the Jews to eat. See LEVIT. CH. xi. 2iand 22.
Many persons, not having observed a heart in in... sects, have denied that they have any : but this is rash. These animals have many parts, so very mi. nute, that they cannot be discovered ; may this not be the case with the hearı? Besides, there are many species, in which this organ may be diftin&ly feeri. Lastly, the humours circulate in insects, and the artea ries have a sort of pulsation; they must, iherefore, either have a heart or something analogous to it.
Lungs have likewise been denied to infects. But, as respiration is necessary to every creature, and as it ! is carried on by means of lungs, which are found in all the other animals, we cannot doubt but insects have them likewise. They are not of the same size, nor the same structure in all creatures, and those of insects are larger, in proportion, than those of other animals. This organ is formed in all, of little vesicles, connected with one another. The air enters by the trachea, and goes out at the same place. Infects likewise have a trachea, which terminates in their lungs, but it is not of the same structure with that in other animals. In these last, it is formed of many cartilaginous rings ; in insects it is nothing but skin, which can be dilated or contracted with ease. The lungs of other animals have branches, which, from the vena cava, disperse themselves through the fubstance of the lungs, in many smaller branches., Insects have the same, and by means of these, the air is distributed to all their members.
and goes ochea, which fructure wit of
In most insects, the intestines are a little different from those in the other animals. The minuteness of their bodies will not admit of so great a number. Accordingly, in many we find nothing but a tube, extending from the mouth to the vent, as may be seen in such as are transparent. It would appear, however, that, with respect to the great gut, it is not in all of the same figure, for the excrements of some caterpillars are round, or cylindrical, and those of oa thers have five furrows. This could not happen but from the structure of the rectum, which is the mould that gives the fæces their figure.
· Round this long tube, are many slender fibres, which answer the purpose of veins and windpipe.
Bees have, towards the extremity of the abdomen