Page:Cyclopaedia, Chambers - Supplement, Volume 1.djvu/703

 F E £

which terminates tbefe. It has fomething of the figure of a crefcent ; and from the bafe of this fort of crefcent there is produced a {hort branch, which feems to have been cut off. The end of this crefcent, examined with the help of glalles, appears articulated, whereas mod of the battledore antenna have their terminating piece not articulated. The fize of the Antenna of fome flies may alfo ferve for a di- stinction, as may alfo the manner in which they carry them. The ichneumon flies have theirs in continual motion, making a kind of mceflant vibrations with them.

The Antenna are of very various forms and fhapes in different genera of the fame clafs of animals, and are very judicioufly made by Reaumur the characters of different genera of the butterfly kinds, among which there are almoft an infinite va- riety of them.

The Antenna of infects in general differ from horns, in that they are moveable at the bafe ; and have befide that power, a number of articulations all along their ftructure, by means of which they are alfo capable of being turned about any way at the pleafure of the animal. The differences of their figure and ftrueture in the butterfly clafs, which are made the marks of the different genera, are tbefe. Thofe of the firft genus are of an equal thicknefs from their origin, till they arrive near their extremity. In all this part they are cylindric, but they are terminated by a large head, and in the whole refemble a club. Thefe have been called clavated an- tenna by authors in general ; but Reaumur chufes to call them the button'd antenna?. The buttons that terminate thefe an- tenna are of a very different figure in the various fpecies. Ma- ny of them are oblong and oval, and refemble an olive. Others are fhorter and truncated, and refemble an olive cut off near the middle, their extremity being flat and circular. The buttons, as well as the cylindric part of thefe antenna, are compofed of feveral parts or joints fitted to one another at the ends. The button alone is ufually compofed of ten, twelve, or fifteen of thefe joints, the pedicle or body of the antenna of twenty, thirty, or more. The joints which compofe the buttons are fhort and annular, thofe which form the pedicles are cylindric, being much more {lender and longer than thefe. Many of the antenna of this genus, when viewed by the mi- crofcope, appear to be befet with hairs, and many others are perfectly fmooth. The greater number of the day butterflies, which we fee continually fettling upon flowers and plants, are of this kind as to their antenna.

The Antenna of the fecond genus of butterflies are, in gene- ral, much fhorter in proportion to the body of the animal than the former. But what diftinguifhes thefe from all other antenna is, that they gradually increafe in thicknefs from their infertion, till they come very near the point or extremity ; but there they are terminated by a {lender fpine, which iflues from the lower part, and is ornamented at the end with a round tuft of hairs. Thefe Reaumur calls the club antenna, as they much refemble the figure of the club, which painters and ftatuaries put into the hands of Hercules. When one of thefe antenna is viewed by the microfcope, its extremity is feen to be rounded or cylindric, but the bottom near where it joins the head is flatted. Thefe fort of antenna are found on thofe fpecies of butterflies, which we frequently fee buzzing about flowers, and never fettling on them, and whofe wings make a noife like thofe of a humble-bee. The antenna of the third genus of butterflies are of the nature of the former, infomuch that they gradually increafe in thick- nefs as they go from the head, but they foon terminate the in- creafe ; and at a fmall diftance from their origin their diameter begins to decreafe, and is carried on in a fmaller fize to the extremity, where it terminates in an oval point. It has no clufter of hairs at the end in the manner of the former. Thefe fort of antenna are in fome fpecies twifted alfo, fo as to repre- fent the horns of a ram. Thefe are found on feveral of the butterflies which frequent our meadows. The fourth genus have antenna which terminate in a fharp point. In this they refemble thofe of the fecond genus; but they differ from thofe, and from all others, in that at a little diftance from their origin they become very thick, and conti- nue of this diameter the greateft part of their length, or very nearly to their end, where they turn a little, and terminate in a fine {harp point ; and this fometimes fupports another point formed of a clufter of hairs in the manner of a pencil. Thefe hairs are always of an extreme finenefs. Thefe antenna have alfo this peculiarity, that their upper furface is rounded, but their other part is formed of two regular equal planes. There enter into the compofition of thefe, as well as of the antenna of other kinds, a vaft number of fmall parts, which are nice- ly jointed at the ends one to another; and on the two flat fides of each of thefe joints, the microfcope difcovers two feries of fine hairs, which ftand in an elegant order. Each is placed near the outer edge of the plane it ftands upon ; and the points of each feries converge and meet together at fome height, fo as to form a fort of cover'd alley all along the antenna, re- fembling the fhady walks in a garden, where the trees planted on each fide join at the top. Many of the larger fpecies of butterflies have thefe fort of antenna; they are ufually thick.

FEE

but fhort in proportion to the length of the creafcure ! § Body.* Mr. Reaumur lias very properly called thefe prifmatic antenna^ as in the greater part of their furface they are regularly of a prifmatic figure.

The Antenna of the fifth genus are thofe which are larger at their origin than in any other part, and gradually diminifti from thence to their extremity, where they terminate in a point ; and in general all thofe which are no larger near their extremity than in any other part. Thefe Mr. Reaumur calls the conic antenna, or the quadrated ones, becaufe they are eafily feen to be compofed of a feries of granules joined one to another, and running like the beads of a necklace from the bafe to the point, only becoming fmaller and fmaller all the Way. In fome of thefe the feveral granules they are compo- fed of are round, in others they are flatted, and in fome they very nicely refemble the joints of the vertebra?. There are a great variety of fpecies of butterflies, which have thefe kind of antenna, and in fome they are very long, in others they are as remarkably fhort.

The fixth genusiof Antenna are thofe of the molt furprtfing ftrueture ; thefe are properly called the plumofe or feathered ones. Thefe appear to the naked eye to be each compofed of a ftalk or pedicle, which continually diminifhes in fize from the bafis to the extremity ; and from each fide of this pedicle there grow plumes placed in the manner of thofe on the bar- rel of a quill, only that they do not ftand fo clofe together. Thofe at the bafe of the pedicle are but fhort, but from that part they become gradually more and more fhort, till at length they have fcarce any difcernible length at the extremity. The microfcope however is neceffary for the giving a true idea of the ftrueture of thefe fort of antenna. When viewed in that manner, the pedicle is feen to be compofed of a great number of joints, and the plumage that grows from it is truly of the nature of that of a common bird's feather ; every filament be- ing really a feather in itfelf, and having its barrel and its plu- mage as in birds. The butterflies which have thefe antenna are eafily djftinguifhed as to fex, the males always having larger and more beautifully plumed antenna than the fe- males, and the plumes upon them (landing out in a much bolder manner. The antenna of this genus, as well as of the others, are moveable at their bafe, and the butterflies often carry them erect, often laid down flat and clofe upon their bo- dies. Some carry them in the manner that a hare does Its ears ; and, as they are moveable alfo, fome hafty obfervers have fancied that thefe creatures had cars. What is moft of all remarkable in thefe is, that every filament of their plumage is moveable on its bafe in the fame manner with the whole anten- na, and the creature often clofes them all together, and often expands them more or lefs wide, and ftops the feveral filaments all together in any angle that it pleafes. But it feems as if the animal had no power of moving them fingly, but that the whole feries on both fides always muff bend inward, or ex- pand together, fo that they always ftand in even rows. Thefe are the variations of nature in thefe fmall parts of thefe fmall animals. They are plainly many of them put together with great artifice and nicety; but we are yet at a lofs td know to what end or purpofe thefe nice organizations were given them, or why all this has been done by that great hand which does nothing in vain. Different people have formed very different gueffes as to their ufes. Some have thought them intended to defend the eyes ; but though this might fcem probable in regard to the fhort plumofe ones, it can never hold good in the {lender and fmooth ones, which can be of no fuch fervice. Others have thought them made for wiping and cleaning the eyes. But this is an unneceffary office, and one they are wholly unfit for : And the forelegs of the creature are always ready for fuch a purpofe, and are renderd much fitter for it by the hairs with which they are covei'd, than the antenna, which in moft cafes are compofed of joints, and are by no means adapted to fuch ufes. Others have called them feelers, and fuppofe that the creature ufed them, as a blind man does a ftaff, to feel out the way, left it mould run againft any thing that would hurt it. But thefe creatures have eyes enough to fee with ; and any one who will obferve them while they walk, will find that they do not protrude thefe before them, but often keep them erect upon the head. If this were their fole purpofe, it is alfo eafy to fee that all that beautiful variety in their forms could not have been neceflary. Poflibly they may be the organs of fmelling, fince we evidently find that many infects have this fenfe in a very exquifite degree, and yet we fee no external organs, except thefe, to ferve for it.

It is poflible that this may be their ufe, but it is mere con- jecture; and indeed the bodies of infects are throughout made of parts fo different from ours, that we can probably form no more idea of the ufe of their organs, than a man born deaf can of that of the ear. They may have fenfes different from ours, and thefe may be the organs of them ; or the hearing or fmell may be performed by them.

The pedicles or ftalks of the feveral antenna of butterflies are always hollow, and many of them are fmooth and glofly re- fembling horn. Of this kind are moft of the plumofe antenna.

And