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C H A P. V.
Of The Respiration Of Insects.
Respiration is /that action of the lungs by which the air enters the bodies of animals and is expelled again without intermission. It is one of the most important functions of animal life, and without which no creature could subsist ; accordingly we find that every thing which lives respires, or performs some function nearly approaching to respiration. If was the necessity of this continual motion which determined the Creator to form in" living creatures, those admirable organs which perform it. It is the fame necessity too which makes us generally confound respiration with life, and consider these things as so strictly combined that they can never exist apart. It is not merely in common language,, that these two terms are considered as synonimous \ the Scripture itself often uses them indifferently. Moses, meaning to indicate the destruction of all animals by the wateis of the deluge, fays that "all *' flesh died that moved upon the earth, both of "fowl and of cattle, and of beast, and of every "thing that creepeth upon the earth, and of every * man ; all in whose nostrils was the breath of life, <; of all that was in the dry land died." Gen, vii. 21,22. David also expresses himself in the same manner, speaking of the death of animals; "if thou takest away their breath, they die and re«* turn to their dust." Psal. civ. 29. St Paul, in the discourse he made at the Areopagus, likewise places respiration among the best gifts of the Deity: " he i,iveth to all life, and breath and all things." Acts xvii. 25. An action so necessary, and which is at the fame time common to all animals, requires that I mould stop a moment to consider it, and endeavour to display all the skill and the wisdom os him who is its author.
Some antient philosphers, supposing that insects had neither wind pipe nor lungs, have denied their respiration; but the air pump, invented by Otto Gerickin , and various experiments have convinced the moderns of the contrary. If we put an insect under the receiver of that instrument and then pump out the air; it first grows weak and then dies. It is not therefore to be doubted but that insects like other' animals have both wind-pipe and lungs. The first gives a free passage to the air and the last like a bellows inhale it when they dilate, and expell it when they contract, if we stop the wind-pipe of animals they can no longer breathe and they die; the fame thing happens to insects when their respiration is obstructed. All insects have not the wind-pipe' in the fame place of the body. In some it is found at the mouth, others in the extremity of their body toward the tail, in which they differ from all other animals.
All forts of air are not proper for respiration j it must be temperate; air either too thick or too thin would destroy life; the one makes animals die in a very short time, and a too long abode in the other does not fail to produce the fame effect. But however necessary air may be for life, some there are which can dispense with it for four and twenty hours. If a^ the end of this period air is restored to them
they they recover their strength and do hot appear to have been incommoded.
But what deserves our particular attention is, that these minute creatures, though air is so necessary to them fin summer, live during the winter with very little respiration if any at all. They are then in a sort of sleep or lethargy, in a state between life aad death. The salt and the viscid humour which transpire from their bodies grow hard by the cold, and form a species of crust arcund them; In this state the pores of their bodies are contracted and in a manner shut: the vital spirits are concentrated in the interior parts of the insect, and they lose nothing of them by transpiration. As they make no motion, nothing' is dissipated ; they remain always in the fame state, arid have no occasion to respire in order to acquire new strength*
We cannot sufficiently admire the goodness of the Creator in providing for the wants of his creatures. If air is necessary for their existence, he gives it to them. The quality and quantity of this cannot be the fame for all animals ; he gives to each the organs necessary for inhaling just what is sufficient for' them, and the kind that suits them* He weighs and deftributes it to them as it were by measure. Men enjoy this precious gift in the fame way with insects; but how few are there who have given themselves the trouble of reflecting on a benefit without which' it would be impossible to live. How have they requited Him-for it? From our birth we have breathed, the
air is common to all animals, and they enjoy it without labour or expence; and therefore instead of being grateful,"men become insensible to so precious a- gift. As each inspiration and each expiration are so many authentic testimonies of the power, of the wisdom and the goodness of God, there is not a
moment moment of our lives which does not invite us to celebrate his perfections and to express our own gratitude. The Psalmist was penetrated with the justice of this reflection. "Let every thing that hath breath "fays he, praise the Lord." Psalm Cl. 6.
C H A P.. VI.
Of The Generation Of Insects.
When a living creature produces another of the fame species with itself, we say that it has engendered it. All generation is preceded by an intercourse between the male and the female. This, is a general rule from which insects are not excepted ; the only difference to be remarked with regard to them is, that the way in which the male insects ceupie with the females is different in different species. However, this commerce fecundates the female and puts her in a condition to lay her eggs when the season hat arrived. The Ephemera is singular in this point ; for it is only after the female has deposited her eggs on the surface of the water that the male fecundates them.
The variety among the eggs of insects is incredible : it may be said to equal the number of species. Without considering the difference in their size, I shall only remark the most striking diversities among them whether from their figure or colours. The. most common figures are the round, the oval, and the conic; but it must be attended to that there are some more and some less so, and that some approach mote to these figures than others. As to colours the dif
H , ference ference is rnore striking. Some like those of some soiders have the splendor of little pearls ; others like those of the silk-worm are yellow and of the cr lour of a grain of millet. Others are of the colour of sulphur, of gold, or of wood. Lastly there are some green and brown, and among thrse last there are various tinges of brown, such as yellowish brown, reddish brown, qhesnut, &c.
The matter which these eggs contain is at first a liquid substance, and afterwards forms the insect, which is very artfully enclosed in the shell. There
'it remains till the superabundant humidity is dissipated, and its members have acquired strength enough to break the egg, when it comes out. At this period it makes a hole in the shell raises up the little broken pieces, stretches forward thehead, which hitherto had
, been bent in tqwards the beliy ; displays its antennæ, and puts them ,in motion; brings out its legs one pair after another, attaching itself with the first pair, to the egg, till the whole body is drawn out.
Alljnsects do not remain equally long in the egg. A few hours is sufficient for some, while it requires many days, and even many months before others, break their prison. Eggs, which during winter have been in a warm place, soon lose their humidity and are hatched prematurely. It is worthy of remark, and must not be forgotten, that those caterpillars which live on green vegetables, never leave their eggs till the herbs and leaves they feed on are sufficiently advanced. Providence has been careful to provide for their necessities, and to insure them of food the. moment they want it, *
Another circumstance not less remarkable, is that many of these eggs, notwithstanding their minuteness and delicacy are able to resist both cold and wet which do not destroy them.. But even though num.