Page:Cyclopaedia, Chambers - Supplement, Volume 2.djvu/686

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T R U

rots this Trunk, and extends it into a perfectly fffiflt piece ; it then directs it into the flower, and thrufts its extremity to the very bottom, where it is affixed to the cup ; this is the cafe, however deep the flower be. When it has been a few minutes in the flower, it draws it out and rolls it up ; and after a few moments,- it extends and plunges it into the flower again : this it repeats four or five times, and then flies* away to another flower.: This is the thing that has occafi- oned the poets to make the butterfly the emblem of incon- ftancy, in its flying immediately from one flower to another ;■ but the truth is, that the flower it leaves is no longer capable of affording it the nourifhment it wants.

There are among the butterflies,, fome which never fettle upon any thing, but are eternally upon the wing in the man- ner of fwallows : thefe feed on the wing as thofe birds do. We often fee them buzzing about a flower in the manner of a bee, and in that cafe they fuibin themfelves in the air with their wings, while they unrol their Trunk, and thruft its extremity into the flower, to fuck from its bottom the honey- dew, which is the common food of them, of the bees,, and of many other infects;

The Trunk of the butterfly is a flat body, being broader than it is thick, and is formed of a matter fome what refcm- bling horn \ if the head of the creature be fqueezed, it be- comes neceflitated to unrol the Trunk, and may thus at any time be made to ihew it at its length. Its origin is juft in that part of its face, where the note in other animals takes its origin ; and hence fome aathors who have obferved it when unrolled, have called thofe butterflies which are poflefTed of It the long- nofed ones ; but this is very improper, as it affuredly fupplies the place of a- mouth. It is always largeft at the irifer- tion, and thence gradually decreafes to a point at the other end. The Trunk of the butterfly may alfo be unrolled, by getting the point of a pin between the circles at the center, and- then drawing it gently from the head, the Trunk will by this means be drawn out to its full length ; and if we tieze the creature a little, by gently premng any part of it, it imme- diately opens a crack, in the middle of which it runs up by de- grees to the origin of bate, and fplits it in a manner into two. It has been much difputed, among the curious obfervers of nature % whether the Trunk be originally Compofed of two parts, or two Trunks laid clofe to one another ;. or whether it were owing to its tender ftru£ture 7 that it was eafily fplit by breaking its parts.

Mr. Bonani was of the firft opinion, and Mr. Riget agreed with him at firft, but he afterwards became of the contrary fentiment ; and thought that they really broke in this fplitting, being originally only one: but Reaumur has determined the queftion in favour of Bonani ; having, by repeated obfervations," found them compofed of two parallel Trunks, nicely and evenly laid fidewife together. This indefatigable fearchcr after truth, examined the ''Trunk in the butterfly, while yet in its cryfalis, and when juft ifluing from it: lie obferves that, in the firft cafe, the Trunk is not rolled up, but is laid evenly lengthwife along the body, and in this ftatc it is eafily feen to be made up of two parallel Trunks ; but in the fucceeding ftate, of juft hatching from the cryfalis, one may fee that it is compofed of two : for one of the firft effort;, of the crea- ture, is to roll this organ up into its fpiral form, and in doing this, the two pieces often gape fo wide afunder, and are rolled up Co irregularly, that it is fcarce to be conceived how the animal will be able to lay them even afterwards. This how- ever is done by feveral times rolling and unrolling it; they join firft regularly at the bafe, and then by degrees all the way along to the point. It fometimes happens that there are difficulties in this, and the parts become folded, wrinkled, or otherwife injured in their figure ; and if all this be not fet right in a few minutes, by the action of rolling and extend- ing it ; it never is done afterwards, but the organ dries in that form, and the creature lofes the whole ufe of it, and is doomed foon to perifh by hunger. Mr. Ray mentions a butterfly with a double Trunk; but Mr. Reaumur never having been able to find any fuch, it is very probable, that as Mr. Ray was un- acquainted with this ftructure of the Trunks of all thefe creatures, he only found one whofe Trunk had never clofed. Reaumur, Hift. Inf. vol. i. P. i. p. 293. The union of the two parts, of which the Trunk in thefe creatures is formed, is too ftreight to be owing merely to their contact: ; were they no better joined, they would frequently open and feparate, in the frequent rolling and unrolling of the whole, for the taking in of food. It is evident, on the con- trary, that they are fattened together by a nice joining, and a very vifcous fluid.

There are among the Trunks of butterflies, only two fuch cf- fential differences, as to deferve a general diftinction ; the one kind of thefe are longer, flatter, and rolled up into more fpi- rals ; the others arc fhorter, thicker, and make fewer turns. The firft referable a fort of thin blades, the others refemble a cord $ fome of the flat ones are two or three inches long, and thick in proportion : thefe are the propereft for a micro- fcopic obfervation, in order to know their true ftructure ; and when examined in this manner, they arc found to be formed in an elegant manner, and made up of fibres, which divide themfelves into a number of rings, and refemble the 3

annular ftruclure of the afpera arterla in large annimals. Some ■ of the Trunks of thefe animals are bright and glofly, both on the under and upper fide ; and fome of them have a number of fmall flat bodies i filling from them which are ufually placed at the extremity, tho' fometimes at a diftance from it ; thefe have been fuppofed by fome, to be a fort of fingers, whofe ufe was to collect together the nourifhment fit to be received into theTrunk ; and others have fuppofed them the organs of fuc- tion: but they appear rather to be only intended by nature, as fupports to the end of the Trunk while employed in fucking, as they have no organisation' proper for anfwering either of the other purpofes affigried to them, and as they are obferved only in the more weak and tender Trunks, the ftrong and thick ones having none of them. The two bodies which form the Trunk of the butterfly, have each of them a hollow running all the way along them, or are each of them pro- perly a feparate canal,, capable of receiving a fluid and con- veying it up into the body of the animal. Reaumur, Hift. Inf. vol. 1. P. 1. p-, 301.

Mr. Reaumur found out their ftructure with great eafe, by* moiftening or foaking them in water after the creature was dead : after this treatment they became much more manage- able and pliant than before, and could be rolled and unrolled at pleafure, and cut tranfverfdy or in any other direction. The matter of which thefe Trunks are formed feems more of the nature of whalebone, than of any other known fubftance ; and, like that, if thus fuppled by foaking in water, they are in fome degree tranfparent, from the thinnefs of their fides ; and when they have been long enough in water, if they are pre/led with the finger, there may be feen a feparate column of water moving about in each. And as this obfervation is moft eafily made on fuch Trunks as have been cut off tranfverfely from the head, thefe receiving the water the moft readily, the whole may in thefe be at pleafure prefled out at the ends where they are cut ; and the joining of the two canals, or parts of the Trunk, along the middle, is more like that of the feathered part of a bird's plume, than any other combination in the parts of the animal world ; and the joining of the two' parts, is fo nice, that there is another or third canal formed by it, which is nearly as clofe at the fides as the other two : this may ferve the creature for the conveying its food as well as the; other two, but it appears more probable that its office is to> convey the air for the creature's refpiration, and that the T?-unk in this manner fcrves in the oflice both of a mouth and a nofe.

The other kind of Trunk s of the butterfly- eh'.fs, are the fhort and thick ones ; thefe are not flat, but roimded like a cord 5 they are very robuft and ftrong, and they terminate in a fharp point, which in fome fpecies is capable of wounding the fin- ger if prefled againft it : in all, however, it is capable of wounding and making its way into the tender fubftance of the leaf of a flower. The manner of the creature's getting its nourifhment is this : it plunges the end of the Trunk into the fubftance of the flower, by means of the hole made by this fharp end, Co far, that its apertures are in the place where the juices extravafatc themfelves, from the wound the point has made ; the point itfelf being often on the other fide, having pierced quite through. When it has thus drained away all the juice it can, it flies to another flower, and acts in the fame manner. There is a fpecies of butterfly, remarkable for having a fort of a figure of a death's head on its breaft ;. this fpecies has a thick Trunk of this kind, fo very fharp at the point, that it is capable of wounding the hand. The action of the Trunk in fucking is eafily feen on giving a piece of fugar to a butterfly, that has been kept without food for fume days, after its being produced out of the cryfa- lis ; many of the fpecies will in this cafe feed on the fugar in the fame manner that they would on the juices of flowers, and will fhew that the ufe of their rolling up their Trunk at times, is the fwallowing what they have received into it. The Trunks of the feveral fpecies of butterflies are as different in colour as in fhape; fome are black, others reddifh, many of a chefnut colour; fome are alfo of a pale brown, and fome of a beautiful yellow; many of them alfo arc hairy on the under fide, and many are fmooth. The thicker Trunks are always fhorter than the flat ones, and have only one canal. Reaumur, Hift. Inf. Vol. 1. P. 1. p. 300. Trunks of Gnats, the inftrument by means of which, the gnat ftrikes the flefh, and fucks the blood from animal bodies. This is a machine well worth an attentive obfervation. As fine and fmall as this inftrument appears, it is neverthelefs of a very complex ftructure. The piercer, or more properly piercers of this inftrument, are all entirely hid in the fheath which makes what we call the Trunk ; and is the only par*: we naturally have offered to our view. Reaumur, Hilt. Inf. Vol. 4, p. 580. feq.

This Trunk appears to be cylindric, in the greateft part of its length ; and is covered with fcales, not unlike thofe on the nerves of the wings of the creature ; and refembling fmall leaves. Near its end, it has a little fweiling, where; there is an oblong button, broader at its infertion than at its point: the end of this button is furnifhed with an aperture, out of which the creature occafionally thrufts a fine point. Manv naturalifts have obferved this point ; Swammcrdam confidered