to the perfect infect. An infect, fubject to metamorphofis is called a larva, as long as it continues under the form it affumed, when it first came from the egg, though many of them, during that time, caft their skin. It is called pupa, under the new form which it acquires, when it has thrown off the appearance of a !arva.

Pupæ are either chryfalids, nymphs, or femi-nymphs. A hard, motionless pupa, that does not eat and fhews obfcurely the members of the future infect, is called a chryfalis. The nymph is a tender pupa, lying at reft, not eating, and which fhews clearly the separate members of the future infect. But the femi-nymph is a running pupa, that eats, and is hardly different from the larva, except in having the vaginæ of the wings, which the larva wants.

The chief differences of larvæ lye in the feet, and in the head. As to the feet, fome larvæ want them altogether, others have them, differing in number and figure. We are not accustomed to fee animals with heads that undergo changes in the form; but this wonderful faculty is fhewn by entomology. For many larvæ have a membranaceous head, that often changes its shape.

Larvæ may be divided into eight claffes, one of these, (the Mida) have a membranaceous head, all the rest have it hard or horny. The firft clafs is called Bracti.. The larvæ that belong to this clafs, have membranaceous and horny feet, of the former, always more than ten, of the latter, fix. All these change into nymphs, and afterwards become Tenthredos. The fecond clafs comprehends the Campa. Their character is, to have never more than ten membranaceous feet, furnished with hooks, and fix horny fest. Thefe change into chryfalids, and then become Lepidoptera.

Simulta is the name of the third clafs. Thefe larvæ have fix horny feet, no membranaceous ones: the mouth furnished with teeth. Thefe change into chryfalids, nymphs or femi-nymphs, and at laft, belong to the orders Coleoptera, Neuroptera, or Aptera.

The fourth clafs is called Ipedes. Their character is fix horny feet, and no membranaceous ones. Mouth without teeth, furnished with a single roftrum. The Ipedes turn into nymphs or femi-nymphs, and thefe into infects of the Hemiptera order.

The fifth clafs are the Serphi. They have fix horny feet, and no membranaceous ones. Mouth without teeth, fur

nished with two rigid roftrums. The Serphi firft become nymphs, and then change into Dytifci or Hemerobii.

The fixth clafs, called Bugones, confifts of fuch larvæ as have a round horny head, furnished with teeth fticking out; no feet. Those change into nymphs, and afterwards become infects of the Hymenoptera order.

The feventh clafs, Rauca, have the head horny, and therefore unchangeable in its figure, but without exferted teeth. No horny feet. The Rauce change into chryfalids or nymphs, and thefe into infects of the Diptera order.

'The eighth and last class is called Mide. The larvæ have a small membranaceous head, capable of changing its figure. Feet membranaceous, or none. All the Midæ pass through the state of nymph, into the order of Diptera, as far as is yet known.

PAGE 64, 1. 15.

Fleas, Onifci, &c. If we may believe Leuenhoeck, fleas, at iffuing from the egg, are worms which change into nymphs before affuming the form under which we know them; if this is fo, they belong to the third class, and not to the firft.

The onisci are viviparous, and fuffer no transformation, confequently they belong to none of the four claffes. If any of them are oviparous as fome have affirmed, they may here find a place,

:

РАСЕ 64, 1, 26.

Ants. Ants do not belong to the second, but to the third clafs accordingly Swammerdam places them there in his HIST. GEN. P. 179. It is probable that Mr Leffer has claffed them thus by an overfight, for Swammerdam, at P. 176, which the author quotes, explains the fecond order of transformations by the example of dragon flies, and not by that of ants,

PAGE 64, 1. 27.

Aquatic flies. All aquatic flies do not belong to the fecond clafs. Many fpecies of them belong to the third as the different forts of Phryganeas; and many to the fourth, as all the Afili.

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go.

PAGE 65, 1. 7.

This is the metamorpholis which flies and Ichneumons underThat is, the greater part of flies with two wings. I do not recollect of ever having obferved any with four wings which belonged to this class.

The Germans give the name of bastard wafps to those infects which the French call Ichneumons. I have obferved the transformations of many fpecies of thefe, but I never faw one that could be referred to the fourth clafs as it is here described. Swammerdam to make this clafs, it would feem, more numerous, has comprehended in it many infects which properly belong to the third, and hence has arisen the error of the author.

Even fix times. fkins ftill oftener. become a chryfalis

PAGE 65, 1. 14.

There are infects which change their I know one caterpillar which does not till it has caft its fkin eight times; and another which changes its skin nine times.

PAGE 66, 1. 5.

Madame Merian relates of a caterpillar that feeds on the lime tree, that its chryfalis was as hard as a piece of wood, and that no force could bend it. P. 11. n. 24. P. 47; but of the truth of this I am in doubt.

The hardness of this chrysalis is a sign that it was dead and dried. When the animals are alive, they are never so stiff and hard. Madame Merian seems to have been afterwards convinced of this; for my Latin Edition which mentions the fame caterterpillar takes no notice of this fingular circumstance.

PAGE 66, 1. 14.

The appearance of a child in fwaddling clothes. All these representations are very imperfect, and require the affistance of fancy to find them out. The most remarkable that I know is that of the chryfalis of the Papilio polychloros. There is actually on its back fome resemblance to a face; but what really deferves attention in these chryfalids is, that when we know in what manner the parts of the infect are arranged in them, it is not difficult to trace the head, the eyes, the antennæ, the probofcis, the thorax, the legs and the abdomen. In nymphs

nymphs all these parts appear more distinctly, and in tho I have called Semi-nymphs they are visible at first fight. PAGE 66, 1. 23.

*Or producing the least confufion. This is obfervable in the nymph of the Chryfomela Afparagi. Its antennæ defcend along its fhoulders: its four firft legs are laid upon its breaft; the other two paffing between the wings, join towards the tail, and the wings themselves are applied close to the abdomen.

This difpofition of the members, is very common in the nymphs of all coleopterous infects.

PAGE 66, 1. 24.

Externally all the limbs. Thus in the nymph of the Scarabous fimetarius we discover all the limbs of the future infect. The Author.

This is feen with the fame facility in the nymphs of all beetles, Tenthredos, Ichneumons and feveral other forts of flies. Lyonet.

PAGE 66, 1. 29.

The colour of chryfalids. The chefnut colour prevails in the cone-shaped chryfalids, but I have never obferved it in the angulated ones.

Befides the colours which the author enumerates, nothing is more common than to find a fort of gilding on the angulated chryfalids. I have even seen some that were all over fo brilliant, that at first fight, one would have taken them for a piece of pure gold.

I do not know that any gilding has been difcovered on the cone-shaped chryfalids; I have seen however a species of those caterpillars called Geometræ, which may be said to be gilded, but with a gold much darker than that of the angulated chryfalids.

This gilding does not appear at first on the chrysalids; it is only gradually affumed as they acquire by degrees their due confiftency. The Alchymifts obferving this production did not fail to draw from it a conclufion favourable to their hopes; but nothing could prove more fallacious; this gilding fo beautiful and fhining, has nothing of gold but its gliftering. It owes all its fplendor to the luftrous white of the body of the animal, which fhining through the yellow, transparent

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cover of the chryfalis, produces an effect fo wonderful. This M. Reaumur difcovered, and he has given a very particular explanation of it in his firft volume, Mem. X.

PAGE 67, 1. 8.

A very gaudy one. To give an example of this; the female of the Phalæna antiqua is a very ugly, ill-shaped animal; but its chryfalis, for the regular diftribution of the black and white marks with which it is generally adorned, is one of the most beautiful of any. On the other hand, the caterpillar Cloporte du Chene is one of the uglieft, and yet it produces a very elegant butterfly.

PAGE 67, 1. 29.

Take the leaft nourishment. Indeed it is perfectly impoffible that they can take any, not only because the animal in this ftate is too weak to be active, but because the skin, which envelopes the chryfalis, covers all the parts of the body, and confines them as in a cafe from which the infect cannot extricate itself till the moment of its appearance in the perfect ftate arrives.

PAGE 68, 1. 12.

Thofe which have not the fame advantage. It is not always on account of the delicacy of their cover, that many infects are careful to fabricate very thick cones which are often impenetrable to the air. There are fome which are much harder and firmer than thole which remain fufpended in the open air, which laft however make very folid cones. The reafon of fuch a diffimilar method of preceeding feems to be that fome nymphs and chryfalids require a flower and more infenfible perfpiration than others, either for their developement in the proper feafon, or for taking the form of a perfect infect. What confirms me in this opinion is, that when I have taken those nymphs and chryfalids which form thick cones out of their lurking places, I have always observed, either that they came forth fooner than ordinary, or that the infects which they produced were imperfect, or that they grew dry, and died without coming forth.

PAGE 6, 1. 15.

* A fort of long wool. The Germans call thefe infects wool