Page:Cyclopaedia, Chambers - Supplement, Volume 2.djvu/712

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ftmctly feen, and are either round protuberances, placed at the two fides of the upper part of the ring ; or two tubes or cylinders, either fo placed or joined together, and elevated above the reft of the furface. They have alio two fligmata near the head j thefe are called anterior, as the others are po- fterior ; but thefe are fmaller than the others, and have been generally overlooked by authors. There are feveral fpecies of thefe worms that are hairy, and fome are prickly. One very Angular fpecies is fo much fo, that it refembles a hedge- hog ; it is of a greenifh white colour, but has three lines run- ning along the back, compofed of three feries of fpots, thofe of the middle line being black, and thofe of the others brown. Thefpines or prickles upon this ftand in the number of ten or twelve on every ring, and are all hooked, and have their points turned toward the hinder part of the body. They only are placed on the back and fides, the belly being perfectly fmooth. See Tab. of Infects, N". 24.

Thefe creatures have no legs ; there are indeed certain flefhy eminences on the under part of the rings of fome of them, which aflift them in walking ; but their common method of moving is by fixing their head to any part, and then drawing. the reft of the body to it. This creature, however, has very little occafion for motion ; its whole bufinefs, in this irate, is to eat, and its parent has {a placed it, that it need not hunt its. food fingly, like other creatures of prey ; but it finds itfelf every way fur rounded with the creatures it is to feed upon, and touched by them before, behind, and on every fide ; nay, they often walk upon its back without any apprehenfion of the danger : They remain in their places till he has cleared them away, by eating them ; and when he has devoured all within His reach, it is then only that he need move his quar- ters, and that but a little way; for he feldom has farther to go than to the fartheft place his head could reach, while he remained fixed in the former place. Reaumur's Hift. Inf.. vol. 6. p. 117.

The way to fee him eat, fo as to diftinguifh the manner of it, is to keep one a few hours without food, and then placing him on a paper, or on the hand, and placing fome of the pu- cerons about him, the manner of his feeding on them will be feen. It appears evidently that he has no eyes, for he tries to find them, only by feeling, ftrctching out his head, and trying every where with h y before, behind,, and on every fide, while his hinder part remains fixed. As foon as he perceives a puceron, he darts his triple weapon into it, and flicks it juft as we do a mouthful of meat upon, a fork; he then draws back the dart into the Gift ring, and that ring into the fecond, and then ufes his mouth, which has a kind of trunks with which lie fucks the juices of the puceron.

When the Ver-puceron is of the white, or otherwife pellucid kinds, it is a very furprifing fight to obferve the manner of the feeding, which is clearly feen through the fkin. The puceron being drawn into the fecond ring of the body, there is ken juft below that an oblong body, which is, at times, darted up to the body of the puceron, and down again from it. The movements of this are very fwift, and the (pace of reft between them but fhort. This is a fort of pump, which fucks in the parts and juices of the animal, and delivers them again to the cefophagus or ftomach, placed behind it. During the fhort fpace of reft, we fee it diftinctly difcharge from its hinder part what it had before received from the animal, into this paflage. This is fometimes only its juices, which look like final! bub- bles of air, and fometimes a great number of little round ifh granules, which are evidently the embryo pucerons, with which we know the body of all the grown ones to be loaded, «.ll the pucerons being breeders.

When the worm is hungry it feeds very voracioufly, when not fo, it eats more at its leifure. The fkin of the puceron Is always thrown out of the- mouth, as foon as its juices and entrails have been fucked, and it then looks perfectly like the exuvia, which the pucerons naturally throw off when they change their (kins. The worm will fuck one of thefe crea- tures thus dry in lefs than a minute, and then lofes no time, but throws it out, and immediately feizes another. In this manner Mr. Reaumur faw one worm eat twenty of thefe crea- tures in twenty minutes, and fuppofes that he continued the fame ravage long afterwards ; for having put him among an hun- dred pucerons, there was not one left after two or three hours. When the worm is placed at its eafe among vaft quantities of them, it does not eat fo very quick, but fecms to amufe itfelf by eating one in two or three minutes. This manner of feed- ing, however, deftroys prodigious numbers, for they feldom reft, but are almoft continually at it; and it is hard to find one of them, at any time, without a puceron in its mouth. £0 that a branch of elder, which is covered on every part with thefe animals for four or five inches, (hall be found wholly cleared in three or four days, by only three or four of thefe worms. Reaumur's. Hift. Inf. vol. 6. p. 127. The pucerons are never free from their enemies ; there is no place where they are feen in any confiderable number, where thefe worms are not alfo found ; and their fecurelt retreats do not preferve them. The bladders of the elm, and other trees ; the galls of the leaves and pedicles of the poplars, and the folded leaves of the fame trees, which are ail inhabited by the pucerons, are all fubjed to be vifited by thefe worms alfo.

They Jo not always immediately make their way into' them; but as fuon as one- of the winged pucerons has efcaped out of the place, the hole at which he came out, lets in one of thefe worms, which foon deftroys all the remainder of the family. Another great misfortune to thefe poor creatures, is, that the worms are not confined to any one fpecies of them, but eat all indifferently.

The anus of the worm is placed in the fold of the two laifc rings of the body, and is almoft continually voiding a blackifh. liquid excrement.

Thefe worms, when full grown, are greatly an over-match for the pucerons ; and it is odd to obferve the young worms in their attacks upon them. A worm juft hatched, and not a third part fo big as the puceron, will immediately, however, attack any one that is next it : The puceron, feeling itfelf wounded, will immediately run away ; but the worm keeps its hold, and, raifing its body by the head, fticks to the pu- ceron, and even kills and fticks its juices while it is carried away. When it has done with this, it gets upon another, and fo on, till it grows and gains ftrength and fize enough to refift the force of the puceron, in endeavouring to carry it away, and then fixing itfelf by the tail among the heaps of them, it feeds at pleafure. When it has eaten till it has ar- rived at its full growth, the time of its transformation into the fly ft ate approaches ; It then ceafes to eat, and crawling along; the leaf or ftalk of the plant, feeks out a proper place" where it may be at reft during its., cry falls ftate. When it has pitched upon the place, it begins to void the vifcous liquor before-mentioned in great quantity from' its. mouth. It extends this over a fpace equal to its body, and then placing itfelf on the place, it becomes fixed there, and moves no more. It draws back its head, and the fkin of the whole body hardens fo as to form a fhell, under which it pa'f- fcs the cryfah's ftate. In this ftate it makes a very beautiful appearance j for the fkin, though become as hard as horn, yet has loft nothing of its tranfparence, but, on the contrary, has gained a yet greater degree of it ; and the nymph of the fty is feen clearly within it, the motion of the heart being very diftinctly vifible.

After this* as the nymph grows every day more and rriore perfect, the eyes, the antenna?, and the feveral other parts, may be diftinctly feen : And this indeed would prove the belt of all fubjects to convince thofe who fuppofe, that maggots are fuddenly changed into flics, and caterpillars into butterflies, of the error of their opinion ; as they might here fee, by the cleareft oecular demonftration, that the change is very flow and regular.

The flies which are produced from thefe worms, are all of the two-winged kind ; but there are feveral different fpecies of them ; the generality of them referable wafps, and have a very flat body, Goedart, who has defcribed fome of thefe flies, was furprized to fee .them very final I, when firft prs- duced from the cryfalis, yet growing very large in a quarter of an hour's time, and that without taking any nourifhment i But this was only owing to their feveral parts having been greatly fqueezed while in the cryfalis, and expanding them- felves when they were at liberty from the compreflion. Thefe are the changes of this kind of lea puceron ; but the other de-* vourer of thefe creatures, which has fix legs, is of a different kind, and indeed is in itfelf reducible to feveral fpecies, fome- of thefe. fix-legged worms becoming four-winged flies, aad others a kind of beetles. Thefe, from their near refemblance to the formica-leo, are by Reaumur diftinctly called puceron- lions. Reaumur, Hift. Inf. vol. 6. p. 131. See the article PvcER'otz-Lioh. Veb. Polipe, in natural hifiory, a name given by Reaumur, and fome other authors, to a fpecies of water- worm, by no means to be confounded with the creature called fimply the polype, and which is fo famous for its reproduction of parts cut off, and for many other fingular properties. See the article Polype.

This Ver-polyps is a fpecies of water-worm, produced from the egg of a tipula, and had this name given it from fome re- markable productions, placed at the anterior and pofterior parts of the body, which are fuppofed to have fome analogy with the parts of the fea-fifh called the polypus. Thefe worms are found in muddy ditches, ufually either crawling upon, or buried in the mud. They are of various fizes, from more than an inch in length, to a fifth of an inch, and are fmooth and even on their furface ; they are compofed of feveral rings, as other infects of this kind, and have a brown fcalyhead, of a regular figure, and much harder than the reft of the body. Juft below the head, on the under part of the body, there are placed two membranaceous productions, which feem fragments of arms ; they are confiderably thick, and are cut off obliquely at the ends, and furnifhed with many hairs. At the other extremity of the body there are placed four other productions, refembling four pieces of cords ; two of thefe are affixed to the middle of the lower fide of the laft ring but one, and the other two, at the joining of this to the laft ring. The anterior pair ferve the creature greatly in its moving, and thefe hinder ones have their ufe in fixing that part of the body in the earthy cafe the creature fometimes makes for itfelf, while the head is at liberty to move every where about in 3 fearch.