i.Manitruncus(theManitrunk). The anterior segment of the trunk, in which the head inosculates, or on which it turns[998]. It includes theProthoraxandAntepectus.1.Prothorax(theProthorax). The upper part or the shield of the manitrunk, inColeoptera,Orthoptera, &c. called by way of eminence theThorax[999]. It includes theOra,Patagia,Umbones, andPhragma.AOra(theOra). The inflexed or inferior lateral margin of theProthorax, separated in many genera from theAntepectusby a suture[1000].BPatagia(thePatagia). Two corneous scales observable inLepidoptera, fixed on each side of the trunk, just behind the head, and covered with a long tuft of hair[1001].CUmbones(theBosses). Two moveable bosses surmounted by a spine, with which theProthoraxof the Coleopterous genusMacropusis armed.DPhragma(thePhragm). TheSeptumthat closes the posterior orifice of theProthoraxinGryllotalpaLatr.2.Antepectus(theForebreast). The underside or breastplate of the manitrunk, and the bed of theArms[1002]. It includes theSpiracula Antepectoralia,Prosternum,Antefurca, andBrachia.ASpiracula Antepectoralia(theAntepectoral Spiracles). A pair of breathing-pores fixed in the membranethat connects theAntepectuswith theMedipectus[1003].BProsternum(theForebreast-bone). A longitudinal or other elevation of theAntepectusbetween theBrachia[1004].CAntefurca(theAntefurca). An internal vertical process of theAntepectus, consisting usually of two branches, which afford a point of attachment to muscles of theBrachia[1005].DBrachia(theArms). The first pair of legs ofHexapods, the direction of which is usually towards the head; when spoken of with the other legs, called theForelegs[1006]. They include theClavicula,Scapula,Humerus,Cubitus, andManus.aClavicula(theClavicle). Thefirstjoint of theBrachium, answering to theCoxain the legs.bScapula(theScapula). Thesecondjoint of theBrachium, answering to theTrochanterin the legs.cHumerus(theHumerus). Thethirdand elongated joint of theBrachium, answering to theFemurin the legs.dCubitus(theCubitus). Thefourthand elongated joint, answering to theTibiain the legs. It includes theCoronulaandCalcaria. .ACoronula(theCoronula). A coronet or semicoronet of spines, observable at the apex of theCubitusorTibiaof some insects.—Ex.DilophusLatr.,FulgoraL.BCalcaria(theSpurs). See the definition underPedes Postici. They include theVelum.aVelum(theVelum). A membrane attached to the inner side of the cubital spur inApisL.[1007]eManus(theHand). The terminal jointed portion of theBrachium, answering to theTarsusin the legs[1008]. It includes thePulvilli,Palma, andDigitus.fPulvilli(thePulvilli). See definition underPedes Postici.gPalma(thePalm). The first joint of theManus, when longer and broader than the subsequent ones, or otherwise remarkable; answering to thePlantain the legs[1009].ADigitus(theFinger). See definition underPedes Postici. It includes theUngula.aUngula(theClaw-joint). See definition underPedes Postici. It includes thePollex,Unguiculi, andPalmula.αPollex(theThumb). A small accessory joint, attached to theUngulaof theManusinMantisF.βUnguiculi(theClaws). See definition underPedes Postici.γPalmula(thePalmlet). A minute accessory joint between the claws, answering to thePlantulain the legs. It includes thePseudonychia.*Pseudonychia(theSpurious Claws). See definition underPedes Postici.ii.Alitruncus(theAlitrunk). Theposteriorsegment of the trunk to which the abdomen is affixed, and which bears the legs and wings[1010]. It includes theMesothoraxandMedipectus, and theMetathoraxandPostpectus.1.Mesothorax(theMesothorax). That segment of the alitrunk which bears theElytra, or the anterior pair of wings, and the intermediate pair of legs[1011]. It includes theCollare,Prophragma,Dorsolum,Scutellum,Frænum, andPnystega.ACollare(theCollar). Thefirstor anterior piece of theMesothorax. In most insects that have a conspicuousProthorax, as theColeoptera, this piece appears scarcely to have a representative; but in theLibellulinait co-exists with it, and is more conspicuous[1012]. It is particularly remarkable inHymenopteraandDiptera.BProphragma(theProphragm). A partition of an elastic substance, rather horny, connected posteriorly with theDorsolum, which passes down into the anterior cavity of the alitrunk, of which it forms theupper separation from that of the manitrunk. It affords a point of attachment to several muscles of the wings, &c.[1013]CDorsolum(theDorslet). The piece which lies between theCollareandScutellum, to which the prophragm is anteriorly attached, and which bears the upper or anterior organs of flight[1014]. It includes thePteropega,Elytra,Tegmina,Hemelytra,Alæ Superiores, andTegulæ.aPteropega(theWing-socket). The space in which the organs for flight are planted. That for the secondary or under-wings is in theMetathorax[1015].bElytra(theElytra). Theupperorgans for flight, when they are without nervures, and uniformly of a thicker harder substance than membrane whether corneous, or coriaceous; lined by a fine membrane; and when closed, united by the longitudinal suture[1016]. They include theAxis,Sutura,Epipleura,Alula, andHypoderma, and are peculiar to theColeopteraandDermaptera.AAxis(theAxis). A small, prominent, irregular process of the base of theElytrum, upon which it turns, and by the intervention of which it is affixed to theDorsolum, in the anterior wing-socket[1017].BSutura(theSuture). The conflux of the sutural or inner margins of the twoElytra, where when closed they unite longitudinally[1018].CEpipleura(theEpipleura). The inflexed accessory margin observable underneath in manyElytra, which covers the sides of the alitrunk and abdomen[1019].DAlula(theWinglet). A small, membranous, wing-like appendage, attached to theElytrumon one side and theFrænumon the other; which probably serves to prevent the dislocation of the former[1020].—Ex.Dytiscus. N. B.A similar organ for a similar purpose is to be found inBlattaand theDiptera.EHypoderma(theHypoderma). The skin, in some species beautifully coloured, that lines theElytra[1021]. N. B.This skin is also found in someHemelytra,but not inTegmina.cTegmina(theTegmina). The upper organs of flight, when of a uniform coriaceous or pergameneous texture, veined with nervures, and lapping over each other[1022]. Ex.Orthoptera[1023].dHemelytra(theHemelytra). The upper organs of flight, when they are corneous or coriaceous at the base and membranous at the apex[1024].—Ex. Theheteropterous Hemiptera. They include theCoriumandMembrana.ACorium(theCorium). The corneous or coriaceous part of theHemelytrum[1025].BMembrana(theMembrane). The membranous part of the same[1026].eAlæ SuperioresvelPrimariæ(theUpperorPrimary Wings). The upper or anterior organs of flight when formed of membrane, or of the same substance with the under-wings[1027]. They include theAxes,Areæ,Areolæ,Neuræ,Stigma,Parastigma, andLobuli.AAxes(theAxes). Several osseous or horny pieces, by which the wing is connected with theDorsolum[1028]. One usually to each area.BAreæ(theAreas). The larger longitudinal spaces into which the wing may be divided[1029]. They include theArea Costalis,Intermedia, andAnalis.aArea Costalis(theCostal Area). That part of the wing lying between the anterior margin and the post-costal nervure[1030]. InHymenopteraandDipterait includes all the space bounded by the nervures that spring from the postcostal.bArea Intermedia(theIntermediate Area). That part of the wing lying between the costal area and the interno-medial nervure, inDiptera; or theAnalinOrthoptera,Hemiptera,Hymenoptera, &c.[1031]cArea Analis(theAnal Area). All that part of the wing which inDipteralies between the internomedialnervure; or inOrthoptera, &c. between the anal nervure and the posterior margin[1032].CAreolæ(theAreolets). The smaller spaces into which the wing is divided by the nervures. They include theAreolæ Basilares,Mediæ, andApicales.aAreolæ Basilares(theBasal Areolets). The parallel areolets of the base of the wing[1033].bAreolæ Mediæ(theMiddle Areolets). The areolets of the wing that lie between the basal areolets and the apical[1034].cAreolæ Apicales(theApical Areolets). Those areolets of the wing that terminate in or very near the apex[1035].DNeuræ(theNervures). Corneous tubes, for expanding the wing and keeping it tense, and to afford protection to the air-vessels—commonly called theNerves. They include theNeura Costalis,Postcostalis,Mediastina,Externo-media,Interno-media,Analis,Axillaris, andSpuria.aNeura Costalis(theCostal Nervure). The first principal nervure of the wing, close to or forming the anterior margin inLepidoptera,Hymenoptera, andDiptera; but sometimes remote from it inTegmina[1036]. It includes thePhialumandHamus.αPhialum(thePhial). A little bag to receive fluid at the will of the insect, by which the weight of the wing is increased. It is found also in the under-wings inColeoptera[1037].βHamus(theHook). A Hook fixed to theCostal Nervure, near its base on the under-side, in the wings of someLepidoptera, in which the tendon runs[1038].bNeura Postcostalis(thePostcostal Nervure). The second principal, and often strongest, nervure of the wing[1039]. It includes theNeuræ Subcostales.αNeuræ Subcostales(theSubcostal Nervures). Nervures springing from the under-side of the postcostal nervure, or from each other; called thefirst,second,third, &c. in the order of their occurrence[1040].cNeura Mediastina(Mediastinal Nervure). A usually slender nervure, springing from near the base of the postcostal; between which and the costal it intervenes. In theLepidoptera Diurna, however, it is often a strong nervure[1041].dNeura Externo-media(theExterno-medial Nervure). Thethirdprincipal nervure of the wing[1042]. It includes theNeura Subexterno-media.αNeura Subexterno-media(theSubexterno-medial Nervure). A nervure that in some cases intervenes between the externo-medial and interno-medial[1043].eNeura Interno-media(the Interno-medial Nervure). Thefourthprincipal nervure[1044]. It includes theNeura Subinterno-media.αNeura Subinterno-media(theSubinterno-medial Nervure). A nervure that sometimes intervenes between the externo-medial and the anal[1045].fNeura Analis(theAnal Nervure). The principal nervure nearest the interior or posterior margin, with which it includes a space often subtriangular, traversed in mostDipteraand manyHymenopteraby another nervure; and in manyTegminaandHemelytraby several[1046]. In these kinds of upper-wing it is in many cases accompanied by a fold; and the part between it and the interior margin seems often capable of separate motion.gNeura Axillaris(theAxillary Nervure). The short nervure, where there is only one, intervening between the anal nervure and the interior margin; replaced in someMuscidæby a spurious nervure[1047].hNeuræ Spuriæ(theSpurious Nervures). Very obsolete nervures, sometimes found in addition to those usually occurring; as inSyrphus[1048].EStigma(theStigma). A corneous spot or plate, supposed to contain fluid, in the anterior margin of the upper wings; often produced by the conflux of the costal and postcostal nervures[1049].FParastigma(theParastigma). A corneous spot between the costal and postcostal nervures, distinct from theStigmaobservable in theLibellulina.GLobuli(Lobuli). One or more rounded portions of the base of the wing, separated from the rest by fissures peculiar to theMuscidæ, and the under-wings of someHymenoptera[1050].fTegulæ(theTegulæ). Small corneous concavo-convexscales, which in many Orders, particularlyHymenoptera, cover and defend the base of theUpper-Wings[1051].DScutellum(theScutellum). A piece, usually triangular, which follows theDorsolum; and inColeopterais often only a continuation of it—placed between the base of theElytraor upper-wings[1052].EFrænum(theFrænum). A piece that lies under the lateral margin of theScutellumandDorsolum, or is adjacent to it; and which in many cases connects with the base of the upper organs of flight, so as to prevent their dislocation, by being pushed too far outwards[1053].FPnystega(thePnystega). A corneous scale or plate, which covers certain pneumatic vessels, usually supported by theScapularia, inLibellulina, &c. becoming dorsal[1054].2.Medipectus(theMid-breast). The underside of thefirstsegment of the alitrunk[1055]. It includes thePeristethium,Scapularia,Mesosternum,Medifurca, andPedes Intermedii.APeristethium(thePeristethium). The anterior piece of theMedipectus, which intervenes between theBrachiaand mid-legs[1056].BScapularia(theScapulars). Two pieces, one on each side theMedipectus, which succeed thePeristethium, and lie between the midlegs and thePteropegaor wing-socket[1057]. It includes theSpiracula Scapularia.a.Spiracula Scapularia(theScapular Spiracles). Two spiracles observable, one in each scapular, inAcrida laurifolia, &c.CMesosternum(theMid-breastbone). The elevated and central part of theMedipectus, between the midlegs, often terminating anteriorly in a mucro; sometimes, as inElater, in a cavity, receiving the mucro of theProsternum[1058].DMedifurca(theMedifurca). A branching vertical process of theEndosternum, which serves as the point of attachment to the muscles that move the midlegs[1059].EPedes Intermedii(theMid-legs). The intermediate pair of legs, consisting of the same parts as the posterior legs[1060].3.Metathorax(theMetathorax). The posterior segment of theAlitruncus[1061]. It includes theMesophragma,Postdorsolum,Postscutellum,Postfrænum,Pleuræ, andMetaphragma.aMesophragma(theMesophragm). A partition of a firm consistence, connected by its posterior margin with thePostdorsolum, and passing down vertically into the mid-chest; serving as a point of attachment to several of the muscles that move the wings[1062]. This, with the prophragm, forms the anteriorcavity of the alitrunk, and with the metaphragm it forms the posterior cavity.bPostdorsolum(thePostdorsolum). The middle-piece between the mesophragm and thePostscutellum. InColeopterait consists of a tense elastic membrane, which is quite covered by theMesothorax[1063].cPostscutellum(thePostscutellum). A narrow channel running from theDorsolumto theAbdomeninColeoptera, forming an isosceles triangle reversed. In other orders it is either a triangular elevation of the middle of the posterior part of thePostdorsolum, or a distinct triangular piece[1064].dPostfrænum(thePostfrænum). InColeopterathe part of theMetathoraxin which thePostscutellumlies, at first nearly horizontal, but posteriorly it takes a vertical direction towards the abdomen. In general it may be defined, the part that intervenes between thePostscutellumand theAbdomen; and which in many cases is connected with the posterior basal margin of the under-wings, and prevents their being pushed too far forwards[1065].ePleuræ(thePleuræ). The space behind the scapulars, on which the lower organs of flight are fixed[1066]. They include theAlæ Inferiores.AAlæ Inferiores(theUnder-wings). The lower or secondary pair of organs for flight[1067]. They include theCommissura,Tendo,Hamuli,Pterygium,Alula, andHalteres.aCommissura(theCommissura). A joint in the costal nervure of the wings ofColeoptera, where they bend to take a transverse fold[1068].bTendo(theTendon). A strong bristle, or bristles observable at the base underneath in the under-wings of manyLepidoptera, which plays in theHamusof the upper-wings[1069].cHamuli(theHooklets). Very minute hooks in the middle of the anterior margin, observable in someHymenoptera, by which the under-wing is fixed to the upper, to cause both to act as one organ in flight[1070].dPterygium(thePterygium). In under-wings this is a small wing-like appendage, fixed at the base of the wing in someLepidoptera[1071].eAlula(theWinglet). A small concavo-convex scarious appendage, fixed behind the wings at their base, in manyDiptera[1072].fHalteres(thePoisers). Small capitate processes or organs, observable under the wings ofDiptera, attended by a spiracle[1073].BMetapnystega(theMetapnystega). A corneous scale or lamina that covers the pneumatic organs in theMetathorax, situated sometimes in thePleuræ, as in theColeoptera; at others in thePostfrænum, as inTenthredoL.; and sometimes, as in theLibellulina, between that part and the abdomen[1074].CMetaphragma(theMetaphragm). A nearly vertical septum or partition, attached behind to thePostfrænum, and usually deeply cleft at its apex inColeoptera, of a rather horny consistence, which forms the upper separation of the second cavity of the Alitrunk from that of theAbdomen[1075]. It affords a point of attachment for many muscles of both alitrunk and abdomen. It includes theSeptula.aSeptula(theSeptula). The lesser ridges and partitions raised on the surfaces of the metaphragm, and on those of other parts of the cavities of the trunk, serving as points of attachment to various muscles[1076].4.Postpectus(thePostpectus). The underside of thesecondsegment of the alitrunk[1077]. It includes theMesostethium,Parapleuræ,Metasternum,Postfurca,Opercula, andPedes Postici.AMesostethium(theMesostethium). A central piece between the intermediate and posterior legs, and bounded laterally inColeopteraby theParapleuræ—along the middle of which, where it exists, theMetasternumruns[1078].BParapleuræ(theParapleuræ). Two pieces, one on each side of thePostpectus, included between theScapularia,Mesostethium, andPleuræ[1079]. They include theSpiracula Parapleuritica.aSpiracula Parapleuritica(theParapleuritic Spiracles). Two spiracles, one in each of theParapleuræofTetyra[1080].CMetasternum(theMetasternum). The central and often elevated part of theMesostethium. Its anterior mucro, inColeoptera, often meets the posterior one of theMesosternum, and sometimes appears to form one piece with it, as inHydrophilus, and manyLamellicornbeetles. Sometimes, as inCetonia vitticollis, it even passes between thearms, and covers theProsternum, or supplies its place. Behind, it often terminates in a bifid mucro. It is not present in many Orders: as in theHymenoptera,Diptera, &c.[1081]It includes thePectines.aPectines(thePectines). Two moveable processes, fixed one on each side by its base below the posterior legs to theMetasternuminScorpio: on the lower side is fixed a series of parallel biarticulate processes, resembling the teeth of a comb[1082].DPostfurca(thePostfurca). A process of theEndosternum, terminating in three subhorizontal acute branches, resembling the letter Y, and forming an acute angle with theEndosternum, to which the muscles that move the hind-legs, &c. are affixed[1083].EOpercula(theOpercula). Plates that cover the vocal spiracles in humming insects; and likewise two large cartilaginous plates fixed to the posterior part of thePostpectus, which cover theTympanain maleTettigoniaF.[1084]Perhaps these may be regarded as a kind ofMetapnystegain a new situation.FPedes Postici(theHind-legs). The pair of legsaffixed to the postpectus[1085]. They include, theAcetabulum,Coxa,Trochanter,Femur,Tibia, andTarsus.aAcetabulum(theSocket). The socket in thePostpectusin which the leg is planted[1086]. It includes thePessella.APessella(thePessella). Two little acute processes, fixed one in each, in the socket of the hind-legs in maleTettigoniæ, which appear designed to keep down theOpercula[1087].bCoxa(theHip). Thefirstjoint of the leg which plays in the socket[1088].cTrochanter(theTrochanter). Thesecondjoint of the leg, by which the thigh inosculates in theCoxa. It appears to have no motion separate from that of the thigh. It is sometimes biarticulate[1089].dFemur(theThigh). Thethirdjoint of the leg, long and usually compressed[1090]. It includes theGonytheca.AGonytheca(theKnee-pan). A concavity at the apex of the thigh, underneath, to receive the base of theTibia[1091].eTibia(theShank). Thefourthjoint of the leg, very long, and usually triquetrous[1092]. It includes theEpicnemis,Molula,Talus,Calcaria, andCoronula.AEpicnemis(theEpicnemis). An accessory joint at the base of theTibiain manyArachnida, which does not appear to have separate motion[1093].BMolula(theKnee-ball). The convex and sometimes bent head of theTibia, armed with a horny process on each side, by which it is attached to the thigh[1094].CTalus(theAnkle). The apex of theTibia, where it is united to theTarsus[1095].DCalcaria(theSpurs). One, two, or moremoveablespines, inserted usually at the apex of theTibia; and in manyCarabiL.,LepidopteraL., andTrichopteraK., in the middle also. They may be regarded as a kind of fingers auxiliary to theTarsus, and furnish often an important character in the discrimination of genera[1096].ECoronula(theCoronula). A coronet or semicoronet offixedspines observable at the apex of the posteriorTibiainFulgora candelaria, &c.fTarsus(theTarsus). Thefifthprincipal portion of the legs; consisting in the majority of insects of 1-5 joints, but in thePhalangidæof sometimes as many as 50[1097]. It includes thePlanta,Digitus, andSolea.APlanta(theInstep). The first joint of theTarsusis so called when it is remarkably long and broad[1098]. It includes theCalx.aCalx(theHeel). The curving part of thePlanta, by which it inosculates with theTibia.BDigitus(theToe). The remaining joints of theTarsustaken together[1099]. It includes theAlluxandUngula.aAllux(theToe-ball). The last joint but one of theTarsus, when remarkable, as in Rhyncophorous beetles (CurculioL.)[1100].bUngula(theClaw-joint). The last joint of theTarsus, which bears the claws[1101]. It includes theArthrium,Unguiculi, andPlantula.αArthrium(theArthrium). A very minute joint at the base of the claw-joint, in most Tetramerous and Trimerous beetles[1102].βUnguiculi(theClaws). One or two pair of moveable incurved claws, which usually arm the apex of theUngula[1103].γPlantula(thePlantula). A minute accessory joint, sometimes attached within the claws to the apex of theUngula[1104]. Ex. TheLucanidæ. It includes thePseudonychia.*Pseudonychia(theSpurious Claws). Two stiff clawlike bristles, that terminate thePlantula[1105].CSolea(theSole). The underside of theTarsus[1106]. It includes thePulvilli.aPulvilli(thePulvilli). Cushions of short hairs very closely set; or of membrane, capable of being inflated,or very soft; or concave plates, which cover the underside, or their apex, of the four first joints of theManusorTarsus, and sometimes even of the ends of theCalcaria, as inCimbex; which act so as to produce a vacuum, and enable the animal to suspend itself, or walk against gravity[1107]. Ex.Timarcha,Buprestis,PrioceraK., theGryllina,Muscidæ, &c.
i.Manitruncus(theManitrunk). The anterior segment of the trunk, in which the head inosculates, or on which it turns[998]. It includes theProthoraxandAntepectus.
1.Prothorax(theProthorax). The upper part or the shield of the manitrunk, inColeoptera,Orthoptera, &c. called by way of eminence theThorax[999]. It includes theOra,Patagia,Umbones, andPhragma.
AOra(theOra). The inflexed or inferior lateral margin of theProthorax, separated in many genera from theAntepectusby a suture[1000].
BPatagia(thePatagia). Two corneous scales observable inLepidoptera, fixed on each side of the trunk, just behind the head, and covered with a long tuft of hair[1001].
CUmbones(theBosses). Two moveable bosses surmounted by a spine, with which theProthoraxof the Coleopterous genusMacropusis armed.
DPhragma(thePhragm). TheSeptumthat closes the posterior orifice of theProthoraxinGryllotalpaLatr.
2.Antepectus(theForebreast). The underside or breastplate of the manitrunk, and the bed of theArms[1002]. It includes theSpiracula Antepectoralia,Prosternum,Antefurca, andBrachia.
ASpiracula Antepectoralia(theAntepectoral Spiracles). A pair of breathing-pores fixed in the membranethat connects theAntepectuswith theMedipectus[1003].
BProsternum(theForebreast-bone). A longitudinal or other elevation of theAntepectusbetween theBrachia[1004].
CAntefurca(theAntefurca). An internal vertical process of theAntepectus, consisting usually of two branches, which afford a point of attachment to muscles of theBrachia[1005].
DBrachia(theArms). The first pair of legs ofHexapods, the direction of which is usually towards the head; when spoken of with the other legs, called theForelegs[1006]. They include theClavicula,Scapula,Humerus,Cubitus, andManus.
aClavicula(theClavicle). Thefirstjoint of theBrachium, answering to theCoxain the legs.
bScapula(theScapula). Thesecondjoint of theBrachium, answering to theTrochanterin the legs.
cHumerus(theHumerus). Thethirdand elongated joint of theBrachium, answering to theFemurin the legs.
dCubitus(theCubitus). Thefourthand elongated joint, answering to theTibiain the legs. It includes theCoronulaandCalcaria. .ACoronula(theCoronula). A coronet or semicoronet of spines, observable at the apex of theCubitusorTibiaof some insects.—Ex.DilophusLatr.,FulgoraL.
BCalcaria(theSpurs). See the definition underPedes Postici. They include theVelum.
aVelum(theVelum). A membrane attached to the inner side of the cubital spur inApisL.[1007]
eManus(theHand). The terminal jointed portion of theBrachium, answering to theTarsusin the legs[1008]. It includes thePulvilli,Palma, andDigitus.
fPulvilli(thePulvilli). See definition underPedes Postici.
gPalma(thePalm). The first joint of theManus, when longer and broader than the subsequent ones, or otherwise remarkable; answering to thePlantain the legs[1009].
ADigitus(theFinger). See definition underPedes Postici. It includes theUngula.
aUngula(theClaw-joint). See definition underPedes Postici. It includes thePollex,Unguiculi, andPalmula.
αPollex(theThumb). A small accessory joint, attached to theUngulaof theManusinMantisF.
βUnguiculi(theClaws). See definition underPedes Postici.
γPalmula(thePalmlet). A minute accessory joint between the claws, answering to thePlantulain the legs. It includes thePseudonychia.
*Pseudonychia(theSpurious Claws). See definition underPedes Postici.
ii.Alitruncus(theAlitrunk). Theposteriorsegment of the trunk to which the abdomen is affixed, and which bears the legs and wings[1010]. It includes theMesothoraxandMedipectus, and theMetathoraxandPostpectus.
1.Mesothorax(theMesothorax). That segment of the alitrunk which bears theElytra, or the anterior pair of wings, and the intermediate pair of legs[1011]. It includes theCollare,Prophragma,Dorsolum,Scutellum,Frænum, andPnystega.
ACollare(theCollar). Thefirstor anterior piece of theMesothorax. In most insects that have a conspicuousProthorax, as theColeoptera, this piece appears scarcely to have a representative; but in theLibellulinait co-exists with it, and is more conspicuous[1012]. It is particularly remarkable inHymenopteraandDiptera.
BProphragma(theProphragm). A partition of an elastic substance, rather horny, connected posteriorly with theDorsolum, which passes down into the anterior cavity of the alitrunk, of which it forms theupper separation from that of the manitrunk. It affords a point of attachment to several muscles of the wings, &c.[1013]
CDorsolum(theDorslet). The piece which lies between theCollareandScutellum, to which the prophragm is anteriorly attached, and which bears the upper or anterior organs of flight[1014]. It includes thePteropega,Elytra,Tegmina,Hemelytra,Alæ Superiores, andTegulæ.
aPteropega(theWing-socket). The space in which the organs for flight are planted. That for the secondary or under-wings is in theMetathorax[1015].
bElytra(theElytra). Theupperorgans for flight, when they are without nervures, and uniformly of a thicker harder substance than membrane whether corneous, or coriaceous; lined by a fine membrane; and when closed, united by the longitudinal suture[1016]. They include theAxis,Sutura,Epipleura,Alula, andHypoderma, and are peculiar to theColeopteraandDermaptera.
AAxis(theAxis). A small, prominent, irregular process of the base of theElytrum, upon which it turns, and by the intervention of which it is affixed to theDorsolum, in the anterior wing-socket[1017].
BSutura(theSuture). The conflux of the sutural or inner margins of the twoElytra, where when closed they unite longitudinally[1018].
CEpipleura(theEpipleura). The inflexed accessory margin observable underneath in manyElytra, which covers the sides of the alitrunk and abdomen[1019].
DAlula(theWinglet). A small, membranous, wing-like appendage, attached to theElytrumon one side and theFrænumon the other; which probably serves to prevent the dislocation of the former[1020].—Ex.Dytiscus. N. B.A similar organ for a similar purpose is to be found inBlattaand theDiptera.
EHypoderma(theHypoderma). The skin, in some species beautifully coloured, that lines theElytra[1021]. N. B.This skin is also found in someHemelytra,but not inTegmina.
cTegmina(theTegmina). The upper organs of flight, when of a uniform coriaceous or pergameneous texture, veined with nervures, and lapping over each other[1022]. Ex.Orthoptera[1023].
dHemelytra(theHemelytra). The upper organs of flight, when they are corneous or coriaceous at the base and membranous at the apex[1024].—Ex. Theheteropterous Hemiptera. They include theCoriumandMembrana.
ACorium(theCorium). The corneous or coriaceous part of theHemelytrum[1025].
BMembrana(theMembrane). The membranous part of the same[1026].
eAlæ SuperioresvelPrimariæ(theUpperorPrimary Wings). The upper or anterior organs of flight when formed of membrane, or of the same substance with the under-wings[1027]. They include theAxes,Areæ,Areolæ,Neuræ,Stigma,Parastigma, andLobuli.
AAxes(theAxes). Several osseous or horny pieces, by which the wing is connected with theDorsolum[1028]. One usually to each area.
BAreæ(theAreas). The larger longitudinal spaces into which the wing may be divided[1029]. They include theArea Costalis,Intermedia, andAnalis.
aArea Costalis(theCostal Area). That part of the wing lying between the anterior margin and the post-costal nervure[1030]. InHymenopteraandDipterait includes all the space bounded by the nervures that spring from the postcostal.
bArea Intermedia(theIntermediate Area). That part of the wing lying between the costal area and the interno-medial nervure, inDiptera; or theAnalinOrthoptera,Hemiptera,Hymenoptera, &c.[1031]
cArea Analis(theAnal Area). All that part of the wing which inDipteralies between the internomedialnervure; or inOrthoptera, &c. between the anal nervure and the posterior margin[1032].
CAreolæ(theAreolets). The smaller spaces into which the wing is divided by the nervures. They include theAreolæ Basilares,Mediæ, andApicales.
aAreolæ Basilares(theBasal Areolets). The parallel areolets of the base of the wing[1033].
bAreolæ Mediæ(theMiddle Areolets). The areolets of the wing that lie between the basal areolets and the apical[1034].
cAreolæ Apicales(theApical Areolets). Those areolets of the wing that terminate in or very near the apex[1035].
DNeuræ(theNervures). Corneous tubes, for expanding the wing and keeping it tense, and to afford protection to the air-vessels—commonly called theNerves. They include theNeura Costalis,Postcostalis,Mediastina,Externo-media,Interno-media,Analis,Axillaris, andSpuria.
aNeura Costalis(theCostal Nervure). The first principal nervure of the wing, close to or forming the anterior margin inLepidoptera,Hymenoptera, andDiptera; but sometimes remote from it inTegmina[1036]. It includes thePhialumandHamus.
αPhialum(thePhial). A little bag to receive fluid at the will of the insect, by which the weight of the wing is increased. It is found also in the under-wings inColeoptera[1037].
βHamus(theHook). A Hook fixed to theCostal Nervure, near its base on the under-side, in the wings of someLepidoptera, in which the tendon runs[1038].
bNeura Postcostalis(thePostcostal Nervure). The second principal, and often strongest, nervure of the wing[1039]. It includes theNeuræ Subcostales.
αNeuræ Subcostales(theSubcostal Nervures). Nervures springing from the under-side of the postcostal nervure, or from each other; called thefirst,second,third, &c. in the order of their occurrence[1040].
cNeura Mediastina(Mediastinal Nervure). A usually slender nervure, springing from near the base of the postcostal; between which and the costal it intervenes. In theLepidoptera Diurna, however, it is often a strong nervure[1041].
dNeura Externo-media(theExterno-medial Nervure). Thethirdprincipal nervure of the wing[1042]. It includes theNeura Subexterno-media.
αNeura Subexterno-media(theSubexterno-medial Nervure). A nervure that in some cases intervenes between the externo-medial and interno-medial[1043].
eNeura Interno-media(the Interno-medial Nervure). Thefourthprincipal nervure[1044]. It includes theNeura Subinterno-media.
αNeura Subinterno-media(theSubinterno-medial Nervure). A nervure that sometimes intervenes between the externo-medial and the anal[1045].
fNeura Analis(theAnal Nervure). The principal nervure nearest the interior or posterior margin, with which it includes a space often subtriangular, traversed in mostDipteraand manyHymenopteraby another nervure; and in manyTegminaandHemelytraby several[1046]. In these kinds of upper-wing it is in many cases accompanied by a fold; and the part between it and the interior margin seems often capable of separate motion.
gNeura Axillaris(theAxillary Nervure). The short nervure, where there is only one, intervening between the anal nervure and the interior margin; replaced in someMuscidæby a spurious nervure[1047].
hNeuræ Spuriæ(theSpurious Nervures). Very obsolete nervures, sometimes found in addition to those usually occurring; as inSyrphus[1048].
EStigma(theStigma). A corneous spot or plate, supposed to contain fluid, in the anterior margin of the upper wings; often produced by the conflux of the costal and postcostal nervures[1049].
FParastigma(theParastigma). A corneous spot between the costal and postcostal nervures, distinct from theStigmaobservable in theLibellulina.
GLobuli(Lobuli). One or more rounded portions of the base of the wing, separated from the rest by fissures peculiar to theMuscidæ, and the under-wings of someHymenoptera[1050].
fTegulæ(theTegulæ). Small corneous concavo-convexscales, which in many Orders, particularlyHymenoptera, cover and defend the base of theUpper-Wings[1051].
DScutellum(theScutellum). A piece, usually triangular, which follows theDorsolum; and inColeopterais often only a continuation of it—placed between the base of theElytraor upper-wings[1052].
EFrænum(theFrænum). A piece that lies under the lateral margin of theScutellumandDorsolum, or is adjacent to it; and which in many cases connects with the base of the upper organs of flight, so as to prevent their dislocation, by being pushed too far outwards[1053].
FPnystega(thePnystega). A corneous scale or plate, which covers certain pneumatic vessels, usually supported by theScapularia, inLibellulina, &c. becoming dorsal[1054].
2.Medipectus(theMid-breast). The underside of thefirstsegment of the alitrunk[1055]. It includes thePeristethium,Scapularia,Mesosternum,Medifurca, andPedes Intermedii.
APeristethium(thePeristethium). The anterior piece of theMedipectus, which intervenes between theBrachiaand mid-legs[1056].
BScapularia(theScapulars). Two pieces, one on each side theMedipectus, which succeed thePeristethium, and lie between the midlegs and thePteropegaor wing-socket[1057]. It includes theSpiracula Scapularia.
a.Spiracula Scapularia(theScapular Spiracles). Two spiracles observable, one in each scapular, inAcrida laurifolia, &c.
CMesosternum(theMid-breastbone). The elevated and central part of theMedipectus, between the midlegs, often terminating anteriorly in a mucro; sometimes, as inElater, in a cavity, receiving the mucro of theProsternum[1058].
DMedifurca(theMedifurca). A branching vertical process of theEndosternum, which serves as the point of attachment to the muscles that move the midlegs[1059].
EPedes Intermedii(theMid-legs). The intermediate pair of legs, consisting of the same parts as the posterior legs[1060].
3.Metathorax(theMetathorax). The posterior segment of theAlitruncus[1061]. It includes theMesophragma,Postdorsolum,Postscutellum,Postfrænum,Pleuræ, andMetaphragma.
aMesophragma(theMesophragm). A partition of a firm consistence, connected by its posterior margin with thePostdorsolum, and passing down vertically into the mid-chest; serving as a point of attachment to several of the muscles that move the wings[1062]. This, with the prophragm, forms the anteriorcavity of the alitrunk, and with the metaphragm it forms the posterior cavity.
bPostdorsolum(thePostdorsolum). The middle-piece between the mesophragm and thePostscutellum. InColeopterait consists of a tense elastic membrane, which is quite covered by theMesothorax[1063].
cPostscutellum(thePostscutellum). A narrow channel running from theDorsolumto theAbdomeninColeoptera, forming an isosceles triangle reversed. In other orders it is either a triangular elevation of the middle of the posterior part of thePostdorsolum, or a distinct triangular piece[1064].
dPostfrænum(thePostfrænum). InColeopterathe part of theMetathoraxin which thePostscutellumlies, at first nearly horizontal, but posteriorly it takes a vertical direction towards the abdomen. In general it may be defined, the part that intervenes between thePostscutellumand theAbdomen; and which in many cases is connected with the posterior basal margin of the under-wings, and prevents their being pushed too far forwards[1065].
ePleuræ(thePleuræ). The space behind the scapulars, on which the lower organs of flight are fixed[1066]. They include theAlæ Inferiores.
AAlæ Inferiores(theUnder-wings). The lower or secondary pair of organs for flight[1067]. They include theCommissura,Tendo,Hamuli,Pterygium,Alula, andHalteres.
aCommissura(theCommissura). A joint in the costal nervure of the wings ofColeoptera, where they bend to take a transverse fold[1068].
bTendo(theTendon). A strong bristle, or bristles observable at the base underneath in the under-wings of manyLepidoptera, which plays in theHamusof the upper-wings[1069].
cHamuli(theHooklets). Very minute hooks in the middle of the anterior margin, observable in someHymenoptera, by which the under-wing is fixed to the upper, to cause both to act as one organ in flight[1070].
dPterygium(thePterygium). In under-wings this is a small wing-like appendage, fixed at the base of the wing in someLepidoptera[1071].
eAlula(theWinglet). A small concavo-convex scarious appendage, fixed behind the wings at their base, in manyDiptera[1072].
fHalteres(thePoisers). Small capitate processes or organs, observable under the wings ofDiptera, attended by a spiracle[1073].
BMetapnystega(theMetapnystega). A corneous scale or lamina that covers the pneumatic organs in theMetathorax, situated sometimes in thePleuræ, as in theColeoptera; at others in thePostfrænum, as inTenthredoL.; and sometimes, as in theLibellulina, between that part and the abdomen[1074].
CMetaphragma(theMetaphragm). A nearly vertical septum or partition, attached behind to thePostfrænum, and usually deeply cleft at its apex inColeoptera, of a rather horny consistence, which forms the upper separation of the second cavity of the Alitrunk from that of theAbdomen[1075]. It affords a point of attachment for many muscles of both alitrunk and abdomen. It includes theSeptula.
aSeptula(theSeptula). The lesser ridges and partitions raised on the surfaces of the metaphragm, and on those of other parts of the cavities of the trunk, serving as points of attachment to various muscles[1076].
4.Postpectus(thePostpectus). The underside of thesecondsegment of the alitrunk[1077]. It includes theMesostethium,Parapleuræ,Metasternum,Postfurca,Opercula, andPedes Postici.
AMesostethium(theMesostethium). A central piece between the intermediate and posterior legs, and bounded laterally inColeopteraby theParapleuræ—along the middle of which, where it exists, theMetasternumruns[1078].
BParapleuræ(theParapleuræ). Two pieces, one on each side of thePostpectus, included between theScapularia,Mesostethium, andPleuræ[1079]. They include theSpiracula Parapleuritica.
aSpiracula Parapleuritica(theParapleuritic Spiracles). Two spiracles, one in each of theParapleuræofTetyra[1080].
CMetasternum(theMetasternum). The central and often elevated part of theMesostethium. Its anterior mucro, inColeoptera, often meets the posterior one of theMesosternum, and sometimes appears to form one piece with it, as inHydrophilus, and manyLamellicornbeetles. Sometimes, as inCetonia vitticollis, it even passes between thearms, and covers theProsternum, or supplies its place. Behind, it often terminates in a bifid mucro. It is not present in many Orders: as in theHymenoptera,Diptera, &c.[1081]It includes thePectines.
aPectines(thePectines). Two moveable processes, fixed one on each side by its base below the posterior legs to theMetasternuminScorpio: on the lower side is fixed a series of parallel biarticulate processes, resembling the teeth of a comb[1082].
DPostfurca(thePostfurca). A process of theEndosternum, terminating in three subhorizontal acute branches, resembling the letter Y, and forming an acute angle with theEndosternum, to which the muscles that move the hind-legs, &c. are affixed[1083].
EOpercula(theOpercula). Plates that cover the vocal spiracles in humming insects; and likewise two large cartilaginous plates fixed to the posterior part of thePostpectus, which cover theTympanain maleTettigoniaF.[1084]Perhaps these may be regarded as a kind ofMetapnystegain a new situation.
FPedes Postici(theHind-legs). The pair of legsaffixed to the postpectus[1085]. They include, theAcetabulum,Coxa,Trochanter,Femur,Tibia, andTarsus.
aAcetabulum(theSocket). The socket in thePostpectusin which the leg is planted[1086]. It includes thePessella.
APessella(thePessella). Two little acute processes, fixed one in each, in the socket of the hind-legs in maleTettigoniæ, which appear designed to keep down theOpercula[1087].
bCoxa(theHip). Thefirstjoint of the leg which plays in the socket[1088].
cTrochanter(theTrochanter). Thesecondjoint of the leg, by which the thigh inosculates in theCoxa. It appears to have no motion separate from that of the thigh. It is sometimes biarticulate[1089].
dFemur(theThigh). Thethirdjoint of the leg, long and usually compressed[1090]. It includes theGonytheca.
AGonytheca(theKnee-pan). A concavity at the apex of the thigh, underneath, to receive the base of theTibia[1091].
eTibia(theShank). Thefourthjoint of the leg, very long, and usually triquetrous[1092]. It includes theEpicnemis,Molula,Talus,Calcaria, andCoronula.
AEpicnemis(theEpicnemis). An accessory joint at the base of theTibiain manyArachnida, which does not appear to have separate motion[1093].
BMolula(theKnee-ball). The convex and sometimes bent head of theTibia, armed with a horny process on each side, by which it is attached to the thigh[1094].
CTalus(theAnkle). The apex of theTibia, where it is united to theTarsus[1095].
DCalcaria(theSpurs). One, two, or moremoveablespines, inserted usually at the apex of theTibia; and in manyCarabiL.,LepidopteraL., andTrichopteraK., in the middle also. They may be regarded as a kind of fingers auxiliary to theTarsus, and furnish often an important character in the discrimination of genera[1096].
ECoronula(theCoronula). A coronet or semicoronet offixedspines observable at the apex of the posteriorTibiainFulgora candelaria, &c.
fTarsus(theTarsus). Thefifthprincipal portion of the legs; consisting in the majority of insects of 1-5 joints, but in thePhalangidæof sometimes as many as 50[1097]. It includes thePlanta,Digitus, andSolea.
APlanta(theInstep). The first joint of theTarsusis so called when it is remarkably long and broad[1098]. It includes theCalx.
aCalx(theHeel). The curving part of thePlanta, by which it inosculates with theTibia.
BDigitus(theToe). The remaining joints of theTarsustaken together[1099]. It includes theAlluxandUngula.
aAllux(theToe-ball). The last joint but one of theTarsus, when remarkable, as in Rhyncophorous beetles (CurculioL.)[1100].
bUngula(theClaw-joint). The last joint of theTarsus, which bears the claws[1101]. It includes theArthrium,Unguiculi, andPlantula.
αArthrium(theArthrium). A very minute joint at the base of the claw-joint, in most Tetramerous and Trimerous beetles[1102].
βUnguiculi(theClaws). One or two pair of moveable incurved claws, which usually arm the apex of theUngula[1103].
γPlantula(thePlantula). A minute accessory joint, sometimes attached within the claws to the apex of theUngula[1104]. Ex. TheLucanidæ. It includes thePseudonychia.
*Pseudonychia(theSpurious Claws). Two stiff clawlike bristles, that terminate thePlantula[1105].
CSolea(theSole). The underside of theTarsus[1106]. It includes thePulvilli.
aPulvilli(thePulvilli). Cushions of short hairs very closely set; or of membrane, capable of being inflated,or very soft; or concave plates, which cover the underside, or their apex, of the four first joints of theManusorTarsus, and sometimes even of the ends of theCalcaria, as inCimbex; which act so as to produce a vacuum, and enable the animal to suspend itself, or walk against gravity[1107]. Ex.Timarcha,Buprestis,PrioceraK., theGryllina,Muscidæ, &c.
III. ABDOMEN (theAbdomen).
TheAbdomenis thethirdor posterior section of the body which follows theTruncus[1108]. It includes theTergum,Venter,Petiolus,Cauda, andAnus.
i.Tergum(theTergum). The upper or supine surface of the abdomen[1109]. It includes theSegmenta Dorsalia, andPulmonaria.1.Segmenta Dorsalia(theDorsal Segments). Transverse segments of the back, the sides of which often lap over and cover those of the ventral segments[1110].2.Pulmonaria(thePulmonary Space). Two longitudinal soft spaces, capable of tension and relaxation, one on each side of the back of the abdomen, in which, where they exist, the dorsal spiracles are planted[1111]. They include theSpiracula Dorsalia.aSpiracula Dorsalia(theDorsal Spiracles). Lateral breathing-pores observable in the dorsal segments, often covered by the preceding segment[1112].ii.Venter(theBelly). The lower or prone part of the abdomen[1113]. It includes theHypochondria,Epigastrium[1114],Segmenta Ventralia, andElastes.1.Hypochondria(theHypochondria). Two portions of segments, one on each side; which in some genera[1115](CarabusL., &c.) intervene between the firstintireventral segment and the posterior part of thePostpectus.2.Epigastrium(theEpigastrium). The first intire ventral segment[1116]. It includes theMucroandTympana.AMucro(theMucro). The central posterior point of theEpigastriumobservable in many of the Orders, which reposes between the posterior legs; and, according to M. Chabrier, is useful to the insect during flight[1117].BTympana(theDrums). Two deep cavities, containing a complex machinery on each side of theEpigastriumin maleTettigoniæ, which are the instruments of sound[1118].3.Segmenta Ventralia(theVentral Segments). Transverse sections of the belly[1119]. In Elytrophorous insects they are usually of a firmer consistence than those of the back. They include theSpiracula Ventralia.ASpiracula Ventralia(theVentral Spiracles).—Breathing-poresobservable in some genera in the intermediate ventral segments, one on each side[1120]. Ex.Dynastes Aloeus, &c.4.Elastes(theElastes). The elastic organs on the ventral segments ofMachilis polypodawhich assist this insect in leaping.iii.Petiolus(theFootstalk). A slender part by which the abdomen of manyHymenopterais united to the trunk, in some genera very long, in others very short, and in others wanting[1121]. It includes theFuniculus,Foramen,Squama, andNodus.1.Funiculus(theFuniculus). A small cartilaginouscord, passing through a minute orifice of thePostfrænum, just above the point where the footstalk is fixed, to an opposite hole above it, which enables the animal the better to elevate or drop the abdomen[1122].2.Foramen(theForamen). The orifice in the abdomen, through which the above cord passes[1123].3.Squama(theScale). A vertical flat scale, observable on the footstalk of the genusFormica, &c.[1124]4.Nodi(theKnots). One or more subrotund protuberances of the footstalk in the genusMyrmica[1125].iv.Cauda(theTail). Where the abdomen grows suddenly slenderer, and terminates in a long jointed tail, as inScorpioandPanorpa[1126]. It includes the Centris.1.Centris(theCentris). The last inflated joint of the tail, terminating in theSting.v.Anus(theAnus). The termination of the abdomen, consisting of the two last segments. It includes thePodex,Hypopygium,Culus,Ovipositor, andAppendices.1.Podex(thePodex). The last dorsal segment of the abdomen[1127].2.Hypopygium(theHypopygium). The last ventral segment of the abdomen[1128].3.Culus(theCulus). The orifice at the end of the anus.4.Ovipositor(theOvipositor). The instrument of oviposition, by which the insect conducts the eggs to their appropriate nidus, and often bores a way to it; the same instrument is by some genera used as a weapon of offence, when it is called theAculeus[1129]. It includes theUnci,Tubulus,Valvæ,Vaginula, andTerebellæ.AUnci(theUnci). Two pair of robust organs, the upper incurved and the lower recurved, with which the anus ofLocustaLeach is furnished[1130].BTubulus(theTubulus). A tubular ovipositor, consisting of several pieces often retractile within each other, like the tubes of a telescope[1131].CValvæ(theValves). Two lateral laminæ, often coriaceous, by which the ovipositor when unemployed is covered[1132].DVaginula(theSheath). A corneous case, withtwo grooves, in which theTerebellaorSpiculaplay[1133].ETerebellæ(theTerebellæ). Instruments by which the insect saws or bores a passage for its eggs to the place in which her instinct directs her to deposit them[1134].5.Aculeus(theSting). The above instrument, when fitted for an offensive weapon[1135]. It includes, besides theValvæandVaginulabefore defined, theSpicula.ASpicula(theDarts). The proper stings which inflict the wound: retractile within the sheath, externally serrulate at the apex[1136]. They include theRetinaculum.aRetinaculum(theRetinaculum). A minute horny moveable scale or plate with which the darts are furnished, which prevents their dislocation by being shot forth too far[1137].vi.Appendices(theAppendages). Other instruments and organs, with which the anus of various insects is furnished. They include—theForceps,Forfex,Furca,Styli,Foliola,Flosculus,Caudulæ,Fila,Mammulæ,Papillæ, andSiphonuli.1.Forceps(theForceps). A pair of anal organs that open and shut transversely, andmeetat their inner margin, or at the apex. Ex.Forficula.2.Forfex(theForfex). A pair of anal organs, which open or shut transversely, andcrosseach other[1138]. Ex. Male ofRaphidia Ophiopsis.3.Furca(theFork). An inflected elastic anal organ, ending in a fork, by which the animal is enabled to leap[1139]. Ex.Podura.4.Styli(theStyles). Rigid, exarticulate, long and narrow anal organs[1140]. Ex.Staphylinus.5.Foliola(theLeaflets). Rigid, exarticulate, dilated, leaf-like anal organs[1141]. Ex.Libellulina.6.Flosculus(theFloret). A small, tubular, lunulate anal organ, with a central style[1142].Fulgora candelaria, &c.7.Cerci(theCerci). Two short, flattish, sublanceolate, jointed, lateral anal organs[1143]. Ex.Blatta.—N.B. Analogous organs are observable in theGryllina, but usually conical and without joints[1144]. InGryllusLatr. they are setiform[1145].8.Caudulæ(theCaudulæ). Two or more slender, filiform or setaceous,jointed, flexile anal organs[1146]. Ex.Lepisma,Machilis,Ephemera.9.Fila(theThreads). Two exarticulate, slender, filiform anal organs[1147]. Ex.Machilis.10.Mammulæ(theMammulæ). Anal protuberances, containing instruments for spinning web[1148]. Ex.Araneidæ. They include theFusi.11.Fusi(theSpinners). Organs, consisting of two retractile pieces, issuing from theMammulæ, and rendering the threads[1149].12.Siphonuli(theSiphonets). Truncated, fistular, setiform anal organs, emitting a saccharine fluid[1150]. Ex.Aphis.
i.Tergum(theTergum). The upper or supine surface of the abdomen[1109]. It includes theSegmenta Dorsalia, andPulmonaria.
1.Segmenta Dorsalia(theDorsal Segments). Transverse segments of the back, the sides of which often lap over and cover those of the ventral segments[1110].
2.Pulmonaria(thePulmonary Space). Two longitudinal soft spaces, capable of tension and relaxation, one on each side of the back of the abdomen, in which, where they exist, the dorsal spiracles are planted[1111]. They include theSpiracula Dorsalia.
aSpiracula Dorsalia(theDorsal Spiracles). Lateral breathing-pores observable in the dorsal segments, often covered by the preceding segment[1112].
ii.Venter(theBelly). The lower or prone part of the abdomen[1113]. It includes theHypochondria,Epigastrium[1114],Segmenta Ventralia, andElastes.
1.Hypochondria(theHypochondria). Two portions of segments, one on each side; which in some genera[1115](CarabusL., &c.) intervene between the firstintireventral segment and the posterior part of thePostpectus.
2.Epigastrium(theEpigastrium). The first intire ventral segment[1116]. It includes theMucroandTympana.
AMucro(theMucro). The central posterior point of theEpigastriumobservable in many of the Orders, which reposes between the posterior legs; and, according to M. Chabrier, is useful to the insect during flight[1117].
BTympana(theDrums). Two deep cavities, containing a complex machinery on each side of theEpigastriumin maleTettigoniæ, which are the instruments of sound[1118].
3.Segmenta Ventralia(theVentral Segments). Transverse sections of the belly[1119]. In Elytrophorous insects they are usually of a firmer consistence than those of the back. They include theSpiracula Ventralia.
ASpiracula Ventralia(theVentral Spiracles).—Breathing-poresobservable in some genera in the intermediate ventral segments, one on each side[1120]. Ex.Dynastes Aloeus, &c.
4.Elastes(theElastes). The elastic organs on the ventral segments ofMachilis polypodawhich assist this insect in leaping.
iii.Petiolus(theFootstalk). A slender part by which the abdomen of manyHymenopterais united to the trunk, in some genera very long, in others very short, and in others wanting[1121]. It includes theFuniculus,Foramen,Squama, andNodus.
1.Funiculus(theFuniculus). A small cartilaginouscord, passing through a minute orifice of thePostfrænum, just above the point where the footstalk is fixed, to an opposite hole above it, which enables the animal the better to elevate or drop the abdomen[1122].
2.Foramen(theForamen). The orifice in the abdomen, through which the above cord passes[1123].
3.Squama(theScale). A vertical flat scale, observable on the footstalk of the genusFormica, &c.[1124]
4.Nodi(theKnots). One or more subrotund protuberances of the footstalk in the genusMyrmica[1125].
iv.Cauda(theTail). Where the abdomen grows suddenly slenderer, and terminates in a long jointed tail, as inScorpioandPanorpa[1126]. It includes the Centris.
1.Centris(theCentris). The last inflated joint of the tail, terminating in theSting.
v.Anus(theAnus). The termination of the abdomen, consisting of the two last segments. It includes thePodex,Hypopygium,Culus,Ovipositor, andAppendices.
1.Podex(thePodex). The last dorsal segment of the abdomen[1127].
2.Hypopygium(theHypopygium). The last ventral segment of the abdomen[1128].
3.Culus(theCulus). The orifice at the end of the anus.
4.Ovipositor(theOvipositor). The instrument of oviposition, by which the insect conducts the eggs to their appropriate nidus, and often bores a way to it; the same instrument is by some genera used as a weapon of offence, when it is called theAculeus[1129]. It includes theUnci,Tubulus,Valvæ,Vaginula, andTerebellæ.
AUnci(theUnci). Two pair of robust organs, the upper incurved and the lower recurved, with which the anus ofLocustaLeach is furnished[1130].
BTubulus(theTubulus). A tubular ovipositor, consisting of several pieces often retractile within each other, like the tubes of a telescope[1131].
CValvæ(theValves). Two lateral laminæ, often coriaceous, by which the ovipositor when unemployed is covered[1132].
DVaginula(theSheath). A corneous case, withtwo grooves, in which theTerebellaorSpiculaplay[1133].
ETerebellæ(theTerebellæ). Instruments by which the insect saws or bores a passage for its eggs to the place in which her instinct directs her to deposit them[1134].
5.Aculeus(theSting). The above instrument, when fitted for an offensive weapon[1135]. It includes, besides theValvæandVaginulabefore defined, theSpicula.
ASpicula(theDarts). The proper stings which inflict the wound: retractile within the sheath, externally serrulate at the apex[1136]. They include theRetinaculum.
aRetinaculum(theRetinaculum). A minute horny moveable scale or plate with which the darts are furnished, which prevents their dislocation by being shot forth too far[1137].
vi.Appendices(theAppendages). Other instruments and organs, with which the anus of various insects is furnished. They include—theForceps,Forfex,Furca,Styli,Foliola,Flosculus,Caudulæ,Fila,Mammulæ,Papillæ, andSiphonuli.
1.Forceps(theForceps). A pair of anal organs that open and shut transversely, andmeetat their inner margin, or at the apex. Ex.Forficula.
2.Forfex(theForfex). A pair of anal organs, which open or shut transversely, andcrosseach other[1138]. Ex. Male ofRaphidia Ophiopsis.
3.Furca(theFork). An inflected elastic anal organ, ending in a fork, by which the animal is enabled to leap[1139]. Ex.Podura.
4.Styli(theStyles). Rigid, exarticulate, long and narrow anal organs[1140]. Ex.Staphylinus.
5.Foliola(theLeaflets). Rigid, exarticulate, dilated, leaf-like anal organs[1141]. Ex.Libellulina.
6.Flosculus(theFloret). A small, tubular, lunulate anal organ, with a central style[1142].Fulgora candelaria, &c.
7.Cerci(theCerci). Two short, flattish, sublanceolate, jointed, lateral anal organs[1143]. Ex.Blatta.—N.B. Analogous organs are observable in theGryllina, but usually conical and without joints[1144]. InGryllusLatr. they are setiform[1145].
8.Caudulæ(theCaudulæ). Two or more slender, filiform or setaceous,jointed, flexile anal organs[1146]. Ex.Lepisma,Machilis,Ephemera.
9.Fila(theThreads). Two exarticulate, slender, filiform anal organs[1147]. Ex.Machilis.
10.Mammulæ(theMammulæ). Anal protuberances, containing instruments for spinning web[1148]. Ex.Araneidæ. They include theFusi.
11.Fusi(theSpinners). Organs, consisting of two retractile pieces, issuing from theMammulæ, and rendering the threads[1149].
12.Siphonuli(theSiphonets). Truncated, fistular, setiform anal organs, emitting a saccharine fluid[1150]. Ex.Aphis.
You will observe, that when thewhole upper-sideof theTruncusis spoken of, it is called theThorax; and as inColeoptera, and some other Orders, the whole of theMesothoraxexcept theScutellumis covered by theThorax, and the whole of theMetathoraxby theMesothoraxandElytra—theThoracic shield, may without danger of mistake be denominated theThorax, as it has always been. When thewhole under-sideof theTrunkis spoken of, it is called thePectus. When thethree Sternumsare spoken of together, they may be called theSternum; and thewhole interior elevationof thePectusmay be called theEndosternum.
Before I confine my observations to theheadof insects, which I propose to consider separately in the present letter, I must premise a few words upon theirbodyin general, or rather itscrust, or external integument. In this we may notice itssubstance, generalform,sculpture,pubescence, andcomposition.
i. I have already noticed thesubstanceof this integument in the preparatory states of insects[1151]; I shall not, therefore, here repeat what I then said, but restrict myself chiefly to the consideration of it as it is found in theirlaststate, in which it is usually firmer than in their previous stages of existence. In this respect, however, it varies much in the different Orders, and even in the different genera of the same Order. In some Coleopterous insects, for instance, it is very hard, and difficult to perforate; while in others it is soft, flexible, and a pin easily passes through it[1152]. And in general, from a substancein hardness resembling horn or shell, it passes through the intermediate degrees of that of leather and parchment, almost to a thin membrane. Yet in all cases there is enough of rigidity and hardness to answer the principal uses of a skeleton—to afford, namely, a sufficient point of attachment for the muscles, and to support and defend the interior organization; so that the play and action of the vital and secretory systems may not be interrupted or impeded.
With respect to the principles which enter into the composition of this integument, very little seems to be known at present; but few insects having been submitted to a chemical analysis. The blister-beetle (Cantharis vesicatoria), from its importance in medicine, has, however, been more than once analysed; and though the products have not been very precisely stated, yet we find amongst them phosphate of lime, albumen, and some other usual components of the substance of vertebrate animals[1153]. But which of these products belong to the integument, and which to its contents, cannot be ascertained, without a separate process for each; which would not, I conceive, be very feasible. The substance, however, of the integument of insects, though we know not its precise contents, which probably vary in different genera, &c., appears not to be exactly of the nature of any of those substances after which it has usually been denominated:it is not properly analogous either to realhorn,shell,skin, orleather, &c. This seems to result from the following circumstance:—Most of the excretions of vertebrate animals, as horn, skin (at least when tanned), feathers, wool, hair, &c. when exposed to the action of fire liquify, more or less, before they incinerate; emitting at the same time a peculiar and disagreeable scent: but upon applying this test to the parts of insects of the different Orders, I found, in every instance, that incineration took place without liquefaction, and was unaccompanied by that peculiar scent which distinguishes the others. Even theclaws, which to the eye appear, as to their substance, exactly like those ofMammalia, birds, &c. burn without melting, and retain their form after red heat. That the insect integument is notcalcareouslike that of theCrustacea, and the shells ofMolluscæ, you may easily satisfy yourself, by immersing them in an acid test. I made this experiment upon portions of insects of several of the Orders, in an equal mixture of muriatic acid and water, and the result was, not only that all hexapods, but octopods,Arachnida, and evenScolopendridæ, upon immersion only emitted a few air-bubbles; while, when the other myriapods,Polydesmus,Iulus,Glomeris, &c. and theOniscidæ, were immersed, a violent effervescence took place; proving the different nature of their substance. It is remarkable that the two great branches of theMyriapods, theScolopendridæandIulidæ(ChilopodaandChilognathaLatr.), should in this respect be so differently circumstanced—the latter having a calcareous integument, and the former not.—A further difference distinguishes these two tribes:oldspecimens of theIulidæusually lose their colour and turnwhite, likeOniscidæ; while those of theScolopendridæretain it.
ii. Theformof insects is so variable, that it can be reduced to no other general rules—than that, for the most part, the length exceeds the breadth, and the breadth the depth, and that the upper surface is usually convex. But to these rules there are numerous exceptions. Thus manyTetyræF. (ScutelleraLatr.), a kind of bug, are as broad as they are long[1154]; in the genusGonyleptesK.[1155]amongst theAptera, andEpeira cancriformis, a crab-shaped spider, the breadth exceeds the length; inCynips, and several otherHymenoptera, inAcridaK.[1156](LocustaF.), and other Orthopterous insects, the depth exceeds the breadth; and in that singular beetle,Eurychora; the cockroach (Blatta), &c. the upper surface is flat.
iii. Thesculptureof the integument of insects is often very remarkable; but as this will call for attention hereafter, I shall only here observe in general, that ornament and variety seem not to be the sole object of those elevations and depressions which form so prominent a feature of many of the animals in question; for by means of these, many important purposes, that at first sight do not strike the observer, may be served: such as giving firmness to the crust in those places where it is most wanted; diminishingits powers of resistance in others, so that it may yield somewhat to the action of the muscles; increasing or deducting from the weight of the body, so as to produce a proper equipoise during its motions, whether on the earth, in the air, or in the water. The depressions of the outer surface of the crust, in many instances, produce an elevation of it in the interior, and so afford a useful point of attachment to certain muscles. This observation seems more especially applicable to those excavations that are common to particular tribes or genera: thus the dorsal longitudinal channel to be met with on the prothorax of most of theCarabiof Linné on the inside of the crust have a corresponding ridge. InLocusta Dux, also, (a Brazil locust,) the same part hasfourtransverse channels, corresponding with which on the inside are as manysepta, or ridges, to which muscles are attached; and those larger impressed puncta denominatedpuncta ordinaria, which distinguish the same part inGeotrupesand many of theScarabæidæ, within are elevated, so as to form a kind of ginglymous articulation with the base of the anterior coxæ. The other impressed puncta so often to be seen on the different parts of various insects, which sometimes so intirely cover the surface that scarcely any interval is discoverable between them, though in many cases they appear to be mere impressions that attenuate but do not perforate the crust—yet in others, perhaps equally or more numerous, they are realpores, which pass through the integument. If, for instance, you take the thoracic shield of the cockchafer (Melolontha vulgaris), and after removing the muscle &c., hold it against the light, with the inner side towards the eye, you will see the lightthrough every puncture: or take the elytra ofGeotrupes stercorarius, or any common beetle in which these organs have punctate striæ, and examine them under a lens on the inside, and you will see distinctly that the punctures pass through the elytrum, and the membrane that lines it[1157]. It is not improbable that in the case last mentioned these pores may be of use, as the spiracles are usually closely covered by the elytra, for the better transmission of the air to those respiratory organs. Whether the pores in the other parts of the body are for transpiration, is more than I shall venture to affirm; but as insects sometimes perspire, at least this has been ascertained with respect to the hive-bee[1158], this must be by the means of some pores.
iv. The integument of insects is often clothed, either partially or generally, withpubescence, or hairs of various kinds—a circumstance which seems to have more than one object. InParnus,Heterocerus,Gerris,Argyroneta aquatica, and some other aquatic insects, the end in view seems to be to keep the water from wetting the crust; and in this case the covering of hairs is dense, silky, and decumbent. Another object is preventing friction from being injurious: thus humble-bees, that from their mode of nidification[1159], are usually more particularly exposed to it, are well clothed with hair; and in those articulations of insects where much friction takes place, we may often observe a dense fringe or coating of the same substance. This you may see in the commonstag-beetle (Lucanus Cervus), where the thorax receives the head; and very remarkably at the same point in the Hercules-beetle (Dynastes HerculesMacLeay): but besides these uses, there is probably one more universal, which will apply as well to those thinly scattered bristles and hairs, here and there one, to be noticed in many insects: but concerning this I can only throw out a conjecture, as I do not recollect ever to have seen any experiments with regard to this use of animal hairs. But may they not act as conductors, either to introduce some invisible fluid into the body in a positive state, or to convey it out, when received by other means, in a negative state? Every one knows that the fur of a cat has electric properties, and there may be an important general use of this kind attached to the fur and hairs of animals[1160]. But, as I said, I give this as a mere conjecture; and only wish it may excite your attention to the subject, and put in exercise your natural tact for experiment.