ENTOMOLOGY.

303

vested, and their shortness in flies and oilier insects, would induceone to believe them not to be in the organs oi' touch : iJr. Barbutsupposes them to constitute or to contain the organs of hearing.That they are tubular, and tilled with air and some kind ofhumour, appears from the antenna: of butterflies immersed inwater.

Of the External Parts of Insects.

The external parts of the bodies of insects, agreeably to theusual anatomical division of those in larger animals, may be divid-ed into the bead, trunk, abdomen, ami extremities.

1. Caput, the Head . It is asserted in the “ FundamentaEutomologix,” that this part in insects is without brain. The dif-ference between the brain and spinal marrow consists in the formerbeing a medullary part organized. We do not deny the existenceof a medullary thread in the heads of insects, but we never coulddiscover it to be organized : hence the hippobosca equina, orhorse-fly, will live, run, nav even copulate, after being deprivedof its bead ; to say nothing of many others which are capable ofliving long under the same circumstances. Insects not being ap-parently furnished with cars, they have been supposed to be inca-pable of hearing ; as we can no more conceive that sense to existwithout ears than vision without eyes. That they are neverthelesssusceptible of any shrill or loud noise, as well as fishes, is indisput-able ; kut it lias been supposed to he in a manner different fromthat of hearing. Mr. Barbut, however, thinks thev possess thissense in a very distinct maimer. Many insects, he observes, arewell known to be endowed with the power of uttering sounds,such as large beetles, the lice, wasp, common fly, gnat, tic. Thesphinx atropos squeaks, when hurt, nearly as loud as a mouse.Now, if insects are endowed w ith the power of uttering sounds, itcertainly must be for some purpose. As they vary their cry oc-casionally, it must certainly be designed either to give notice ofpleasure or pain, or some affection in the creature who possessesit. “ The knowledge of their sounds (lie justly argues) is un-doubtedly coil fined to their tribe, and is a language intelligible tothem only ; saving when violence obliges the animal to exert thevoice of nature in distress, craving compassion; then all animalsunderstand the doleful cry. For instance, attack a bee or was])near the hive or nest, or a few of them : the consequence of thatassault will be, the animal or animals, by a different tone of voice,will express his or their disapprobation or pain; that sound isJ-.nown to the hive to be plaintive, and that their brother or bre ;thren require their assistance ; and the offending party seldomescapes with impunity. Now, if they had not the sense of hear-ing, they could not have known the danger their brother or bre-thren were in by the alteration of their tone.” The organ of hear-ing, in our author’s opinion, is situated in the antenna?; both fromtheir situation in the part of the head most favourable to such or-gans, their inward structure being moveable, the ears of most in-ferior animals being so. lie lias never considered the antenna' ascither offensive or defensive, but has observed them to be endowedwith an exquisite sense of feeling; that the animal appeared to bein agony when its antenna' were pinched ; and that it takes rare toavoid the touching of any hard substance with them roughly.“ This tenderness m the organ of hearing (says lie) is common toall animals; and insects seem to be particularly tender in theseparts by quickly withdrawing them from the touch.” Mr. Barbu Ifurther observes, that the antemnr of all insects are composed ofjoints varying in si/e, form, and number. Those who are chieflyroutined to live under water have their antenna: in general shorterman those who live on land.^ Some who roam at large in the air,have them long and slender. They are all hollow, and are ren-deted flexible by the joints, which are very visible in the horns ofthe crab and lobster. Tins hollowness, in our author’s opinion, isto receive the sound communicated to the extremities of the an-tenna' by the repercussion of the air alfected by anv noise-; andconvey it, by means of the joints, from one to another, till it ar-rives in that lessened degree of tone best suited to the timid natureuf the animal, hi this, circumstance there may be many varia-tions in point of perfection in those organs; the* strength, utility,and degree of power in receiving sound, being proportioned totlie necessities of the animals, different in their nature and requi-res. In most animals, the entrance to the auricular organ is pa-11 l ous ; but in this case the animal would suffer great inconveni-

ence from such an organization, as the organ would often beclogged with dirt, &c. Several entomologists have doubted,whether insects have the sense of sir.eli, no organ being found iuthem adapted to that purpose : and although it was evident theyhad a perception of agreeable and fetid effluvia, it was thought tobe in a manner altogether unknown to us. Mr. Barbut is of opi-nion, that the organs of smell reside in the palpi or feelers. Manyinsects have four end some six, two of which are in general cheli-form, in order to assist the insect in conveying its food to itsmouth. The palpi are in continual motion, the animal thrustingthem into every kind of matter, as a iiog would do his nose,smelling and searching after food. Insects which apparently donot possess palpi or spiral tongues, have undoubtedly some organconcealed within the mouth analogous to them in function andutility ; the fleshy proboscis of the fly is thrust into every sub-stance in which the animal expects to find food ; and when it isextended, nearly in the middle are situated, in our author’s opi-nion, two upright palpi, which, no doubt, perform in their turnsome office, perhaps that of smell.

Tongue. Many insects have no tongue, nor make any soundwith their mouth ; but for this purpose some use their feet, otherstheir wings, and others some elastic instrument with which they arenaturally furnished.

Eyes. Most insects have two ; but the gyrinus lias four, thescorpion six, the spider eight, and the scoiopendra three. Thevhave no eye-brows, but the external tunic of their eyes is hardand transparent like a watch-glass; their eyes have no externalmotion, unless it be in the crab. They consist for the most partof one lens only ; but in those of the butterfly, diptera?, and many,of the beetles, they are more numerous. I’ugett says, he disco-vered 17,325 lenses in the cornea of a butterfly, and Lieuwenhoek,SOO in a fly.

Antennje. Of these tiiere are in general two (unless four beallowed to some species of crabs,) and pliieed oil the fore-pah ofthe head. They arc peculiar to insects, and are plaiuly distin-guishable from the tentac.uls? of the vermes, in being crnstaceous;.and from the palpi of insects, which are more numerous, placednear the mouth, and are sometimes wanting. As the antenna: areof great moment in distinguishing the various kinds of insects, weshall enumerate and explain the several different forms of them.1. Setacex, are those which grow gradually taper towards the ex-tremity. ft. Filiformes, sucli as are of the same thickness through-out. 3. Moniliformes, are filiform, like the preceding, hut con-sists of a series of round knobs, like a necklace of beads. 4. Cla-vata?, such as gradually increase in size toward the extremity. 5.Capitals?, are clavatx, hut have the extremity somewhat round.6. Fissiies, are capitals?; but have the capituhim, or knob, dividedlongitudinally into three or four parts, or lamina', as in the scara-b;vi. 7. Perfoliata', are also capitatx ; but have the capitulum hori-zontally divided, as in tin? dermestes. 8. IVctinala?, so calledfrom their similitude to a com!), though they more properly re-semble a feather, as in the moths and eluteres. This is most ob-vious in the male. y. Aristala?, such as nave a lateral hair, whichis cither naked or furnished with less hairs, as in the fly ; B;e-viores, those which are shorter than the body; longiortv, thosewhich are longer than the body ; mediocrcs, those which are ofthe same length with the body; all three of which varieties aiedistinguishable in the cerambjees.

Palpi, or Feelers, resemble filiform, articulated, moveableantenna'. They are most commonly four in number, sometimessix ; they are sufficiently distinguished from antenna?, in beiimnaked, short, and always placed at the month.

Os, the Mouth, is generally placed in (lie anterior part of thehead, extending somewhat downwards. In some insects it isplaced under the breast, as in the chermes, coccus, cancer (crab,)and curculio.

P. o strum, or Proboscis , is the mouth drawn out to a Faridpoint : in many of the hemiptera class it is bent downward towardthe breast and belly, as in the cicada, nepa, notonecta, cimex(bug,) aphis, and remarkably so in some curcuhonos.

Maxill.t, the Jaws, are two in number, sometimes four, amiat othei times more ; they are placed horizontally ; the inneredge of them in some insects is serrated or furnished with liitieteeth.

Lingua, the Tongue, in some insects is taper and spiral, as in

tin*