are dignified with the title of perfect? Who can from which junction a whitish nervous cord profind an inftance in any other creature that can ceeds, correfponding to the fpinal marrow of the come in competition with this ?" fuperior animals, which extends the whole length of the body, forming in its courfe twelve or thir teen knots or ganglions, from each of which small nerves branch out to different parts of the body. The existence of this medullary thread in the heads of infects is not denied by those who follow Linnæus, in aflerting that infects have no brain, but they could never difcover it to be organized like the brain; and hence, say they, the hippobofca equina, or horfe fly, will live, run, may even copulate, after being deprived of its head; to fay nothing of many others which are capable of liv ing long under the fane circumftances. But, the knots or ganglions which are formed in the courfe of the larger nerves, perform in a great mentire the function of the brain; indeed each of thefe ganglions may be confidered as a fubordinate brain; and thus it may be easily conceived ..ow the various parts which derive their nerves from any one of thefe ganglions, fhould be enabled to perform their different functions, after they have been feparated from the other parts of the body, and deprived of ail connexion with the brain. On this difpute we fhall only obferve, that the wildom of the Creator is fo confpicuous in all his works, and fuch furprifing art is difcovered in the mechanism of the body of every creature, that it is very difficult, if not impoffibie to fay where it is moit, and where it is leaft, to be perceived. Thofe who are defirous of attaining a fyftematic knowledge of infects, ought first to acquire the terms made ufe of in the fcience, that they may be able rightly to denominate every part of an infect. The ftudent fhould first know what an infect is, left he mistake HIPPOCAMPI, and other amphibious animals, for them, as was formerly done; or confound them with VERMES, which Linnæus firft diftinguished from infects, and which differ as effentially from them as the clafs MAMMALIA do from birds. Every infect is furnished with a head, antennæ, and feet, of all which the vermes are deftitute. All infects have fix or more feet; they refpire through pores on the fides of their bodies, which are termed fpiracula: their fkin is extremely hard, and ferves them inftead of bones, of which they have internally none. From this definition, the acus marina is evidently no infect. But the antennæ placed on the fore part of the head conftitute the principal diftinction. Thefe are jointed and moveable in every part, in which they differ from the horns of other animals: they are organs conveying fome kind of fenfe; but we have no more idea of what this kind of fenfe is, than a man has, who, without eyes, attempts to determine the particular action of the rays of light on the retina of the eye, or to explain the changes which from thence take place in the human mind. That they are the organs of fome kind of fenfe, is apparent from their perpetually moving them forward; yet the hard cruit with which they are invested, and their shortnets in flies and other infects, would induce one to believe them not to be the organs of touch: Mr Barbut fuppofes them to confitute or to contain the organs of hearing. That they are tubular, and filled with air and fome kind of humour, appears from the antennæ of butterflies immerfed in water. SECT. II. Of the EXTERNAL PARTS of INSECTS. THE external parts of the bodies of infects, agreeably to the ufual anatomical divifion of thofe in larger animals, may be divided into the head, trunk, abdomen, and extremities. Infects not being apparently furnished with ears, they have been supposed to be incapable of hearing; as we can no more conceive that fenfe to exift without ears than vifion without eyes. That they are nevertheless susceptible of any thrill or loud noife, as well as fithes, is indisputable; but it has been fuppofed to be in a manner different from that of hearing. Mr Barbut, however, thinks they poffefs this fenfe in a very diftinct manner. Many infects, he obferves, are well known to be endowed with the power of uttering founds, fuch as large beetles, the bee, wafp, cominon ily, gnat, &c. The fphinx atropos fqueaks, when hurt, nearly as loud as a moufe. Now, if intefts are endowed with the power of uttering founds, it certainly must be for fome purpose. As they vary their cry occafionally, it muft certainly be defigned either to give notice of pleature or pain, or fome affection in the creature who poflefles it. "The knowledge of their founds he july argues) is undoubtedly confined to their tribe, and is a language intelligible to them only; faving when violence obliges the animal to exert the voice of nature in diftrefs, craving compaffion; then all animals understand the doleful cry. For instance, attack a bee or wasp near the hive or neft, or a few of them: the confequence of that affault will be, the animal or animais, by a different tone of voice, will exprefs his or their difapprobation or pain; that found is known to the hive to be plaintive, and that their brother or brethren require their affiftance; and the offending party feldom escapes with impunity. Now, if they had not the fenfe of hearing, they could not have known the danger their brother or brethren were in by the alteration of their tone." I. CAPUT, the HEAD. It is afferted in the Fundamenta Entomologie, that this part in infects is without brain; but it is certain that a number of the larger infects, as the lobiter, crab, &c. have a foft fubitance very much resembling brain, from which the optic and other nerves take their rife; and the irritating of this fubftance is obferved to throw the animal into convulfions; from which it may be concluded, that infects, as well as the A proof, ftill more decifive, occurred to his ob four fuperior claffes of animals, quadrupeds, birds, fervation, in a large fpider in St James's Park. reptiles, and fishes, have a brain, though it be This creature had made a very large web on a fmaller in proportion to their body. The brain in wooden railing: and was, at the time he obferved moft infects is fituated a little above the fopha- it, on one of the rails at a confiderable distance gus; it divides into two large branches which fur- from the place where a large fly entangled itself. round the fophagus, and unite again under it, Nevertheless, the moment the Hy was entangled, the the spider became fenfible of it; though, from the fituation of the rail, he could not poflibly have feen it. In this, however, Mr Barbut might poffibly be deceived; because the spider was perhaps alarmed by the tremulous motion of the threads, occafioned by the fluttering of the fly; which he might well know how to distinguish from their vibration by the wind. The organ of hearing, in our author's opinion, is fituated in the antennæ; both from their fituation in the part of the head mott favourable to fuch organs, their inward ftructure being moveable, the ears of moft inferior animals being fo. He has never confidered the antennæ as either offenfive or defenfive, but has obferved them to be endowed with an exquisite sense of feeling; that the animal appeared to be in agony when its antennæ were pinched; and that it takes care to avoid the touching any hard fubftance with them roughly." This tenderness in the organ of hearing (fays he) is common to all animals; and infects feem to be particularly tender in these parts by quickly withdrawing them from the touch." Mr BARBUT further obferves, that the antennæ of all infects are compofed of joints varying in fize, form, and number. Those who are chiefly confined to live under water have their antennæ in general fhorter than those who live on land. Some who roam at large in the air, have them long and flender. They are all hollow, and are rendered flexible by the joints, which are very vifible in the horns of the crab and lobfter. This hollowness, in our author's opinion, is to receive the found communicated to the extremities of the antennæ by the repercuffion of the air affected by any noife; and convey it, by means of the joints, from one to another, till it arrives in that leffened degree of tone beft fuited to the timid nature of the animal. In this circumftance there may be many variations in point of perfection in thofe organs; the ftrength, utility, and degree of power in receiving found, being proportioned to the neceffities of the animals, different in' their nature and requifites. In molt animals, the entrance to the auricular organ in patulous; but is this cafe the animal would fuffer great inconvenience from fuch an organization, as the organ would often be clogged with dirt, &c. However much it has been doubted by entomologifts, it seems very evident, that infects enjoy the faculty of fmelling; nay, that it is the moft perfect of all their fenfes. Beetles of various forts, nitidula, the different species of dormestes, sylphs, flies &c. are attracted at a very confiderable diftance, by the fmeil of ordure and putrid bodies, and refort in fwarms to the fpots in which they occur, either for the purpose of feeding or laying their eggs. Thus alfo the common blue flefl-lly, is allured by the ftrong smell of the aurum dracuntium, which is much the fame as that of carrion, and depofits its eggs on it; in the fame manner, the .cadaverous fmell of the flowers of the flapelia birsuta, leads thefe flies to depofit their eggs on them. But, though it is thus evident that infects have a perception of agreeable and fetid effluvia, entomologifts are not at all agreed as to the feat of that particular fenfe. Mr Barbut and others are of opinion that the organs of fmell refide in the palpi or feelers; obferving that the palpi are in continual motion, the animal thrufting them into every kind of matter, as a hog would do his nofe, fmelling and fearching after food. The fenfe of fmelling is fuppofed by other naturalifts to refide in the antennæ: Bafter fuppofed it to be fituated about the entrance of the fpiracula or refpiratory organs; and Dumeril published a differtation, in 1799, in which he attempts to prove this laft to be its fituation. But Latreille, who had adopted the opinion of those who believe the antennæ to be the organs of fmell, in his Precis du Cara&are des Genres, published in 1796, notwithstanding the arguments of Dumeril, till holds by his former opinion, in another work, entitled les Genres et les Familles des Insectes, fince published. The following are his reafons for favouring this opinion: 1. Smell is produced by the action of the air, impregnated with odoriferous particles, on the nervous or olfactory membrane, which tranfmits the fenfation.-If infects be endowed with an organ, furnifhed with fimilar nerves, adapted for receiving impreffions from air charged with odoriferous particles, fuch organ many be confidered as that of fmell. Should the antennæ prefent a tiffue of many nerves, why may not that tiffue be fuppof ed capable of tranfmitting odour? Would not this idea be more fimple, and more agreeable to anatomical principles, than that which fixes the feat of fmell at the entrance of the fpiracula?-2. Many male infects have their antennæ more developed than the females; a circumstance eafily explained, if thefe organs are allowed to be the feat of fmell. 3. Certain it is, that moft of those infects which live or depofit their eggs on putrid animal or vegetable matters, ftagnant waters, &c. are almost uniformly diftinguished by a greater developement of the antennæ; fuch, for inftance, as the beetle, fylphs, leather-eaters, tipulæ, &c. Thefe requiring a more perfect fenfe of smell, arc fuitably organized. 4. A great number of infects, which are entirely rapacious, have fimple antennæ; and those which are fedentary, have none at all; fuch are fome of the fpiders. 5. Infects difcover their haunts and food by the fenfe of fmell. Latreille deprived feveral infects of their antennæ, and found they inftantly fell into a ftate of infenfibility, and feemed to know neither their habitations nor their food, though placed close by them. Were fuch experiments as this profecuted, the question might foon be decided: by coating the antenna of infects with varnish, and placing them near their natural food, it might easily be known whether the antennæ were the organs of fmell; if they were, the animal could not be fupposed to find its way to the food, and vice versa. 6. Nerves terminate the antennæ, the articulations of which, though externally covered with a pretty thick membrane, are hollow, lined with a soft substance, frequently of a watery confiftence, the extremities of which, when expofed to the air, may receive impreffions from it. The antennæ have been fuppofed by fome to be the organs of touch; but this opinion is opposed by Latreille, who feems to think that the fenfe of touch, at leaft in certain fpecies, is fituated in the paws or extremities of the fore legs. The palpi or feelers in fpiders and fome other infects feem to poffels poffefs the fenfe of touch in an eminent degree; but these palpi are confidered by many rather as the organs of tafte. TONGUE. Many infects have no tongue, nor make any found with their mouth; but for this purpose fome ufe their feet, others their wings, and others fome elaftic inftrument with which they are naturally furnished. EYES. Moft infects have two; but the gyrinus has 4, the fcorpion 6, the spider 8, and the fcolopendra 3 They have no eye-brows, but the external tunic of their eyes is hard and transparent like a watch-glafs; their eyes have no external motion, unless it be in the crab. They confift for the moft part of one lens only; but in those of the butterfly, dipteræ, and many of the beetles, they are more numerous. Pugett says, he difcovered 17,325 lenfes in the cornea of a butterfly, and Lieuwenhoek 800 in a fly. ANTENNE. Of these there are in general two (unless 4 are allowed to fome fpecies of crabs), and placed on the fore-part of the head. They are peculiar to infects, and are plainly diftinguish able from the tentacula of the vermes, in being cruftaceous; and from the palpi of infects, which are more numerous, placed near the mouth, and are fometimes wanting. As the antennæ are of great moment in diftinguishing the various kinds of infects, we fhall enumerate and explain the feveral different forms of them. Setacea, are thofe which grow gradually taper towards the extremity. Filiformes, fuch as are of the fame thickness throughout. Moniliformes, are filiform, like the preceding, but confift of a feries of round knobs, like a necklace of beads. Clavate, fuch as gradually increase in fize toward the extremity. Capitate are clavate, but have the extremity fomewhat round. Fiffiles are capitata; but have the capitulum, or knob, divided longitudinally into 3 or 4 parts, or laminæ, as in the fcarabæi. Perfoliata are alfo capitate; but have the capitulum horizontally divided, as in the dermeftes. Pectinata, fo called from their fimilitude to a comb, though they more properly refemble a feather, as in the moths and elateres. This is most obvious in the male. Arifate, fuch as have a lateral hair, which is either naked or furnished with leffer hairs, as in the fly; Brevio res, those which are shorter than the body; Longiores, thofe which are longer than the body; mediocres, thofe which are of the same length with the body; all three of which varieties are diftinguishable in the cerambyces. PALPI, or Feelers, resemble filiform, articulated, moveable antennæ. They are most commonly 4 in number, fometimes 6; they are fufficiently diftinguifhed from antennæ, in being naked, fhort, and always placed at the mouth. Os, the Mouth, is generally placed in the anterior part of the head, extending fomewhat down wards. In fome infects it is placed under the breaft, as in the chermes, coccus, cancer (crab), and curculio. ROSTRUM, or Probofcis, is the mouth drawn out to a rigid point: in many of the hemiptera clafs it is bent downward toward the breaft and belly, as in the cicada, nepa, not onecta, cimex (bug), aphis, and remarkably fo in fome curculiones. VOL. IX. PART 1. MAXILLE, the Jaws, are two in number, fometimes four, and at other times more; they are placed horizontally; the inner edge of them in fome infects is ferrated or furnished with little teeth. LINGUA, the Tongue, in fome infects is taper and spiral, as in the butterfly; in others it is flefly, resembling a probofcis, and tubular, as in the fly. LABIUM fuperius, the upper Lip, is firuated above the jaws; as in the fcarabæus and gryllus. STEMMATA, or Crowns, are three fmooth he mifpheric dots, placed generally on the top of the Head; as in moft of the hymenoptera, and others. II. TRUNCUS, the TRUNK, is that par which comprehends the breaft or thorax: it is fituated between the head and abdomen; and has the legs inferted into it, that its parts may be diftinctly determined. It is divided into thorax, scutellum, and sternum. The THORAX is the back part of the breast, and is very various in its fhape. It is called den tatus, when its fides are armed with points; spi nosus, when its back is furnished with them as in the cerambyx; and marginatum, when its margin is laterally dilated, as in the filpha and caffida. SCUTELLUM, or Escutcheon, is the pofterior part of the thorax: it is frequently triangular; and appears to be divided from the thorax by an intervening future, as in moft of the coleoptera. The STERNUM is fituated on the inferior part of the thorax; it is pointed behind in the elateres, and bifid in some of the dytifci. III. The ABDOMEN is in most insects distinct from the thorax; it is the pofterior part of the body of the infect; and is composed of a number of annular fegments, which ferve occafionally to lengthen or shorten it, and to contain the organs of chylification, &c. SPIRACULA are little holes or pores, placed fingly on each fide of every fegment of the abdomen; through these the infect breathes; and if oil be applied fo as to ftop them up, it proves fatal to most of them. TERGUM, the Back, is the fuperior part of the abdomen. VENTER, the Belly, is the inferior part. ANUS, is the pofterior part of the abdomen, perforated for the evacuation of the 'excrement. This part alfo frequently contains the organs of generation. IV. ARTUS, the LIMBS, or EXTREMITES, are the various inftruments of motion. PEDES, the Legs, are generally fix. There is an exception to this, however, in the clafs Aptera, many of which have 8; as acari (mites,), phalangii, moft of the aranei (fpiders), fcorpiones, and cancri (crabs.) The onifcus has 14, and the iuli and fcolopendri ftill more. The firft joint of the leg, which is generally thickeft, is called femur ; the ad which is generally of the fame fize throughout, tibia; the 3d, which is jointed, is diftinguished by the name of tarsus and the laft, which in most infects is double, by that of unguis. The legs of infects, in general, are named from the various motions they produce a Cursorii, from that of running, which are the moft numerous; saltatorii, from that of leaping; natatorii, from that of fwimming, &c.-In the salta torii, the thighs are remarkably large, by which B means they are able to leap to a confiderable di tance, as in the gryllus, grafshopper, &c. In those of the natatorii, the feet are flat, and edged with hairs, which answer the purpose of oars in afifting them to fwim, as in the dytifcus-Mutici, are fuch feet as have no claws.-Chel, or claws, are the fore fect enlarged towards their extremities, each of which is furnished with two leffer claws, which act like a thumb and finger; as in the crab. ALF, Wings the inftruments which enable the infect to fly. These are membranous and undivid. ed, except in the inftance of the phalana ahtcite, in which they are in part divided. Most in fects have 4; the diptera clafs, and the coccus, however, have only two. The wing is divided into its fuperior and inferior furfaces: its anterior part in a butterfly, is that towards the anterior margin, or next to the head; its pofterior part, that towards the anus; its exterior part, that towards the outer edge; and the interior, that next the abdomen. The Ale are called Plicatiles, when they are folded at the time the infect is at reft, as in the wafp; opposite to thefe are the Plone, which are incapable of being folded. Erede, fuch as have their fuperior furfaces brought in contact when the infect is at reft; as in the ephemera, libeliu'a puella and virgo, and papiliones (butterflies.) Patentes, fuch as remain horizontally extended when the inf.et is at reft; as in the phalana geometræ, and mcft of the libellulæ. Incumbentes, fuch as cover horizontally the fuperior part of the abdomen when the infect is at reft. Dexe are incumbentes, but not horizontally, the outer edges declining towards the fides. Revere, are deflexa, with this addition, that the edge of the inferior wings projects from under the anterior part of the fuperior ones. Dentate are thofe in which the edge is ferrated, or fcolloped: Caudat, thofe in which one or more projections in the hinder wings are extended into procefies. Reticulate, when the velfels of the wings put on the appearance of network, as in the hemerobius perla; the two anterior wings generally become fupe. rior, and the pofterior ones inferior, in moths, when their wings are clofed; but the anterior wings are called primary, and the inferior ones secondary, in butterflies, as none can properly be called inferior, when the wings are all erect. Colores, the colours, are felf-apparent and variors; but according to their feveral fhapes, they take the different names of punce, dots; macule, Epots; fascle, bands, which frequently run across and fometimes furround the edge of the wings; frige, freaks, which are very flender facfciæ; and line, lines, which are longitudinally extended. Ocellus, is a round fpot, containing a lefler fpot of a different colour in its centre. Stigma, another term introduced by Linnæus, fignifies the fpot, or anaftamofis, in the middle of the wing near the anterior marein; it is conspicuous in mot of the hymenoptera' and neuroptera, and even in the coicoptera. The fingle or double kidney-fhaped fpot, fituated in the fame part of the anterior wings, and frequently occuring in the phalanx paganæ, is diftinguished likewife by the nate of stigma Elytra, the plural of elytron. The upper wings, which are of a hard fubftance, in fome degree referbling leather, and which in moft infects are of a very hard texture, but in others flexible, are called dytra; their fuperior frface is generally convex, their inferior one' concave. When the infect flies, they are extended; and fhut when it refts, clofing together, and forming a longitudinal future down the middle of the back, as in the coleoptera. They are of various fhapes. Abbreviate, when fhorter than the abdomen. Truncata, when longer than the abdomen, and terminating in a tranfverfe line. Feftigiata, when of equal or greater length than the abdomen, and terminating in a tranfverfe line. Serrata, when the exterior margin towards the apex is notched or ferrated, as in fome of the bupreftes. Spinosa, when their forface is covered with fharp points or prickles. Seabra, when their furface is fo uneven as to grate against the fingers. Strieto, when marked with fender longitudinal furrows. Porcata, when with elevated longitudinal fulci or ridges. Sulcata when thefe ridges are concave. Hemelytra, when the fuperior wings are of a middle fubftance betwixt leather and membrane; either totally fo, as in the grylli; or partially fo, as in the cimices, nepa, and notonecta: Thefe are commonly named hemipters. Holteres, poifers, (a term alfo introduced by Linnæus), are little heads placed on a ftalk or peduncle, most frequently under a little arched fcale. They are found only in the clafs diptera, and appear to be nothing more than the rudiments of the hinder wings. CAUDA, the Tail, in most infects is, Simplex, fimple, capable of being extended, and again drawn back at pleafure. In the crab and fcorpion, however, it is Elongata, elongated, or lengthened out. Setacea, bristle-shaped, or taper; as in the raphidea. Trifeta, confting of three briftles; as in the ephemera. Furcata, forked, as in the podura. Forcipata, refembling a pair of forceps; as in the forficula. Foliofa, refembling a leaf; as in the blattæ, grylli, and fome fpecics of cancri. Telifera, armed with a dart cr fing; as in the fcorpion and panorpa. Aculeus, the fting, an inftrument with which they wound, and at the fame time inftil a poifon; with fuch the bee, wafp, fcorpion, &c. are furnished. EXPLANTION of PLATE CXXVH. Fig. 1. ANTENNE PECTINATE, or feathered antennæ; as in the phalene, moths. ANTENNE PERFOLIATE, or perfoliated; as in the dereftes and dytifcus. 2. 2. 4. 5. 6. 7. ANTENNE FISSILES, or fiihle, divided into la nine at the extremity, as in the fcarabai, beetles. ANTENNE CLAVATE, or club-shaped, as in the papilio, butterfly. ANTENNA MONILIFORMES, like a necklace of beads; as in the chryfomela. ANTENNE SETACEA, fetaceous, or briftlefhaped; as in many of the phalene. ANTENNE ARISTATE, furnished with a lateral hair, as in the fy. 8, 9. a Caput, the head. b Palpi, the feelers. Antennæ, or horns. d Oculi, the eyes. e Thorax |