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fizes of the worms or maggots bred from the eggs of diffe- rent flies were of great ufe in the perfecting the preparations ; for while the larger fort eat the more flefhy parts, where the veflels are large and but few in number, the middle-fiz'd maggots got into the interfaces of the more vafcular parts, and the moft minute of all, which are ufually alfo the molt numerous, kept about the furface, and eat away between and among the capillary veflels. Hebmjireit de Vermibus Anatomicor. adminiftris.

The maggots produced from flies are not the only animals fit for this kind of bufinefs. There are feveral fpecies of beetles of the fmaller kinds, whofe eggs hatch into a fix- leg'd worm, which eats as much and as nicely as the fly- maggots. All thefe may be employed very fuccefsfully to the preparations of the parts of animals. Thefe nice anatomifts are not confined to animal fubftances : They often exert their power alfo on vegetables. Many of them feed on the leaves and fruits of plants ; and fome fpe- cies of thefe work fo nicely, that they eat away all the outer membrane and internal parenchymatous fubftance of the leaves, fo as only to leave the net-like plexus of veflels ftanding. Yet thefe being unhurt fhew the true figure of the leaf, and are a fort of vegetable fkeletons, but very poorly imitated by art in the common way, by rang mace- rations in water ; this method ufually destroying and warn- ing away many of the fmaller veflels, which the tender mouths of thefe creatures fpare. If they exert their fkill often upon leaves in this manner, they do it alfo fometimes with equal if not greater fuccefs upon fruits. As in the leaves, thofe which have the tenderer!: parenchyma and the firmer! ribs, fucceed beft ; fo alfo it is in fruits. The leaves of the rufcus or butcher's-broom, are often found thus beautifully anatomis'd ; and of all fruits, none fucceeds fo well as that of the ftramonium, or thorn-apple. Where-ever this plant grows in any plenty, the fruit toward autumn while it is yet full of juice is attacked by a fmall worm, which eats away all the parenchyma, and leaves every veflel ftanding in its place ; and this not only in the outer coat of the fruit, but in the very inner cells of the feeds. Thefe veflels remain exactly in the fhape of the fruit, and, growing white with the air, exhibit the moft elegant and beautiful fkeletons imaginable, while yet ftanding on the plant. The animal which effects this, is a hexapode worm produced from the egg of a fmall beetle ; and differs very little from fome of thole which fo elegantly eat away the flefhy parts from the injected anato- mical preparations. Thefe are gregarious animals like fome fpecies of the fmaller caterpillars, and numbers of them are always at Work together on the fame leaf or fruit, fo that the fkeleton is foon made. They begin by piercing a num- ber of little holes into the fubftance of the leaf, and thence burrow under the integument till they meet one another ; and this being done all over the leaf, they leave it, and go to work upon another.

Transformation of Insects. See the article Transfor- mation.

Insects in Amber. Scarce any thing in natural hiftory has more perplexed the writers on that fubject, than the finding Infeffs intombed in amber. Naturalifts were, for a long time not well acquainted with the true nature and origin of the fubftance itfelf ; and while they made erroneous conjec- tures about it, there was no great hope of their falling into the true account of its receiving thefe creatures. Pliny mentions a lizard, and Martial a whole viper buried in am- ber ; and Mercatus in the Metallotheca Vaticana, and fome other writers, have defcribed and figured fmall fifties in it. The account of a whole viper mult needs be a mere chi- mera ; and the other large animals, which are pretended to be buried in it, the effect of fraud. Some artful perfon finding means to fplit the amber, and making a hollow to receive the creature, clofed it together again, perhaps by means of heat, and then polifhed over the furface to conceal the cheat.

Tho' the larger animals are not to be expected to be found naturally included in amber, yet we have daily and incon- teftible proofs, that Infe£ls i and thofe of feveral kinds, con- tinually are fo., Hartman's Hift. Succ'in. There is one very eafy way of diftinguifhing alfo whether thefe are real and natural curiofities, or whether art has been concerned in them ; which is by examining at what depth in the mafs the creature lies. Infers naturally em- bedded in amber, are always found near its furface, or at leaft, there are few found otherwife. The artificially bu- ried creatures are always lodged m or near the center. The reafon of this is plain ; for the artift knows that the deeper the crea&ure lies, the better his art will be concealed ; and that if he had lodged it near the furface, the natural tranfpa- rence of the thin plate of amber which lay over it, would have fhewn the fallacy by bringing the artificial hollow too near the eye. Phil. Tranf. N° 248. p. 21. The too great beauty, folidity, and perfection of the piece of amber, in which an InfeSl lies, is alfo a very great reafon to fufpedt that there is fallacy in the cafe. When the artift is at the pains of introducing a fly into a piece of amber, it is moft worth his while to chufc out a fine folid. and tranfpa-

renf piece for it ; becaufe it will fell belt when done, and will bear his Working on it better than a coarfe and lhattery one. But nature who has not quite fo much confulted the fancy of the pin-chafer, generally has lodged thefe animals, or parts of them, in. the lefs folid pieces of. amber, and fuch as have flaws and cracks. A perfectly uniform and folid piece of amber with an infect: in itj may generally therefore be condemned as artificial ; for the natural amber that has thefe creatures embodied in it, is ufually compofed of a num- ber of crufts or coats, but imperfectly cohering together, and has often cracks and clefts in it reaching to the furface, and the legs of wings or fome part of the included Infeft often hangs out from the fiirface. When a piece of coarfe amber is found with an InfeEl thus bedded in it, the whole may be concluded the work of nature alone, and the fpeci- men a truly valuable curiofity. There are fome finer that are natural, but they are very fcarce. The Infetts really bdried by nature in amber make a very different appearance, in regard to the manner of their prefervation ; for fome of them are feen in all their beauty and natural fplendor 3 others have nothing of this, but have a coat of fhining am- ber thinly fpread over them, and the whole mafs covering that, they refemble amber-flies in other amber; but a o- r eat many are foul and imperfect. Phil. Tranf. N° 248. jp. 2.1* Their poftures alfo, are as various as their appearance ; fome feem as if they had been torpid or dead, when taken into the amber ; others have the appearance of havingbeen taken in alive, their limbs being extended, and the whole creature appearing as if ftruggljng hard to get out of the prifon. Some pieces of amber contain a fingle and perfect Infeft, others have a mutilated lnfs£i or a part of one only, and the fingle leg or wing of a fly is more common than any thing elfe ; but on the other hand, there have been found pieces of amber, containing each a large number of Infects^ and thofe fometimes all of the fame fpecies, fometimes dif- ferent. Hartman's Hiftoria Succini.

Thefe are the general appearances of the real and of the fic- titious curiofities of the amber kind. The reality of many is unqueftionable ; and many authors in order to account for their coming there, had recourfe to the fuppofition of amber's being the refin of fome fpecies of tree. They thought, that as this refin ran down the trunk, the fly might be taken and included in it ; but this is not only a falfe account of the origin of amber, but if it were true, it would not clear up the point : for of all the refins which we know, and which are continually dropping from trees, where Infers in abundance are alfo found, we never fee any of them thus intombU Philof. Tranf. N° 248. p. 23. Others, who faw the wcaknefs of this argument, have aflert- ed, that thofe things which appear to be Infe&s in amber, arc not really fuch, but that we miftake the cracks and flaws in the amber for real bodies. But this fuppofition is eafily prov- ed to be equally erroneous, by examining the bodies them- felves in broken pieces of the amber; in which they will be found really and truly animal remains, and in every part of the fame internal ftructure with that of the animal itfelf. The true account of the matter is, that the amber itfelf is a foflile fubftance and bitumen condenfated into a folid body, and that this is done in the earth.

We often find, that flies, bees, ants, and other Tnfe£fs, la bad weather betake themfelves to the ground, and bury themfelves alive remaining in a torpid ftate, perhaps during the whole winter, perhaps for a fhorter period of time* During this time amber is formed by the condenfing a fluid bitumen into a folid fubftance; and if while fluid it falls on the places where the Jnfeffs He, it muft needs incorporate them into itfelf, and fhew them in its hardned ftate. The greater part of the Infeffs found naturally included in amber, are of thofe kinds which we know do thus hide themfelves in the earth in winter. And it is from hence, that the ge- nerality of Infefts in amber are found in a contracted po- fture, fuch as they lie in during their ftate of reft. Some few indeed feem as if they had ftruggled in order to fet themfelves at liberty ; thefe are probably fuch as were en- tangled in the tough bitumen, either at the time of their firft coming into the earth, or near the period of their ftay there, when they either had not yet fallen into the tor- pid ftate of the others, or were roufing out of it. Some pieces of amber arc fhewn indeed in the cabinets of the cu- rious, containing flies in very lively poftures, and fome with the male and female in coition. The firft of thefe are to be greatly fufpected as impoftors, and the latter wholly con- - demned as fuch. For the time during which the creatures are buried under ground, and half dead with the cold, is cer- tainly not the feafon for propagation. See the article Sue-*

CINUM. Aquaticl-as-ECTS. There is an Jnfeci of a very peculiarly am- phibious kind, which Mr. Reaumur has accurately defcribed in the Memoirs of the Paris Accademy. Many animals are aquatic for a part of their lives, and pafs the reft on dry land; but this Angular creature always contrives to have its head and tail both in the water, and the intermediate part of its body out. To conceive the manner in which this is effected, we muft confider its figure. It is compof«d, like

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