Letter XXXIII
EXTERNAL ANATOMY OF INSECTS.
TERMS, AND THEIR DEFINITION.
Having shown you our little animals in every state, and traced their progress from the egg to the perfect insect, I must next give you some account of their structure and anatomy. And under this head I shall introduce you to a microcosm of wonders, in which the hand of an ALMIGHTY workman is singularly conspicuous. One would at first think that the giant bulk of the elephant, rhinoceros, or hippopotamus, must include a machine far more complicated, a skeleton more multifarious in its composition--covered by muscles infinitely more numerous--instinct with a nervous system infinitely more ramified--with a greater variety of organs and vascular systems in play, than an animal that would scarcely counterpoise a ten-millionth portion of it. Yet the reverse of this is the fact; for the Creator, the more to illustrate his wisdom, power, and skill, has decreed that the minute animals whose history we are recording, shall be much more complex in all the above respects than these mighty monarchs of the forest and the flood. Of this in the present and subsequent letters you will find repeated and scarcely credible instances, which in every rightly constituted mind are calculated to excite, in an extraordinary degree, those sensations of reverence and love for the INVISIBLE AUTHOR of these wonders, and that faith and trust in his Power and Providence, which an attentive survey of the works of Creation has a natural tendency to produce. And you will not only be struck by this circumstance, but equally by the infinite variations in the structure that will present themselves to your notice; and that not sudden and per saltus, but by approaches made in the most gradual manner from one form to another. And all along, where the uses of any particular organ or part have been ascertained, if you consider its structure with due attention, you will find in it the nicest adaptation of means to an end: a circumstance this, which proves most triumphantly, that the POWER who immediately gave being to all the animal forms, was neither a blind unconscious power, resulting from a certain order of things, as some philosophists love to speak[903]; nor a formative appetency in the animals themselves, produced by their wants, habits, and local circumstances, and giving birth, in the lapse of ages, to all the animal forms that now people our globe[904]; but a Power altogether distinct from and above nature, and its ALMIGHTY AUTHOR[905].
I trust that what I have here advanced will excite your attention to the subject I am now to enter upon; and I flatter myself, that although at first sight it may promise nothing more than a dry and tedious detail of parts and organs, you will find it not without its peculiar interest and attraction.
This department of the science--the Anatomy of Insects--may still be regarded as in its infancy; and considering the almost insuperable difficulties which, from the minuteness of the objects, oppose themselves to the skill and instruments of the entomological anatomist, we can scarcely hope that it will ever attain to that certainty and perfection to which, as far as the larger animals are concerned, anatomy has arrived. Yet infinitely more has been accomplished than might have been expected, and new accessions of light are daily thrown upon it. When we consider what has been done by Malpighi, Leeuwenhoeck, and especially Swammerdam, we admire the patience, assiduity, and love of science, that enabled them, in spite of what seemed insurmountable obstacles, to ascertain, the first with respect to the silk-worm, and the latter in numerous instances, the internal organization of these minute creatures, as well as their external structure. Reaumur, and his disciple De Geer, extending their researches, have also contributed copiously to our knowledge in this branch of our science.
But in this field no one has laboured so indefatigably and with so much success as the celebrated Lyonnet; and though his attention was confined to one object--the caterpillar of the goat-moth (Cossus ligniperda F.),--every one who studies his immortal work must admire the patient and skilful hand, the lyncean eye, and keen intellect, that discovered, denuded, and traced every organ, muscle, and fibre of that animal. Much is it to be regretted that his proposed works on the pupa and imago of the same insect, which, he informs us, were far advanced[906], were never finished and given to the world. Our regret, however, is in some degree diminished by the elaborate work of M. Herold on the butterfly of the cabbage (Pieris Brassicæ), before eulogized[907]; in which he has done much to supply this desideratum.
In more modern times, besides Herold, MM. Latreille, Illiger, Marcelle de Serres, Savigny, Ramdohr, Treviranus Sprengel, Audoin, Chabrier, and, above all, M. Cuvier in his celebrated Lectures on Comparative Anatomy, have considerably extended the boundaries of our knowledge in this department: and much of what I have to say to you in my letters on this subject, will be derived from these respectable sources. In the exterior anatomy of insects, I flatter myself that I shall be enabled to make some material additions to the discoveries of my predecessors; though few have occurred to me with respect to their internal organization.
In treating of the anatomy of the vertebrate animals, it is usual, I believe, to consider, first, the skeleton and its integuments, whether of skin or muscle, and their accessories; and afterwards the organs of the different vital functions and of the senses. But in considering the anatomy of Insects, the difference before stated[908], observable between them and the sub-kingdom just mentioned, as to their structure, renders it advisable to divide this subject into two parts--the first treating of their external anatomy, and the second of their internal.--I shall begin by drawing up for you a Table of the Nomenclature of the parts of their external crust; its appendages and processes[909], external or internal, accompanied by definitions of them; and followed by such observations respecting them as the subject may seem to require for its more full elucidation.
Anatomists have divided the human skeleton into three greater sections--the Head, the Trunk, and the Limbs. That of insects, likewise, is resolvable into three primary sections, but without including the limbs (which, as being appendages, and therefore secondary, had best be considered under the section of which they form a part), for the abdomen in insects, as well as the rest of the body, being covered with a crust, and forming a distinct part, may be properly regarded as a primary section. And in fact these three parts may be received as primary under another view--the head, as containing the principal organs of sensation; the trunk, as containing those of motion; and the abdomen, as containing those of generation[910]. Under each of these primary sections, I shall consider its respective organs, members, and parts.
You are not to expect to find every part included in the following Table in every insect; since it has been my aim to introduce into it, the most remarkable of those that are peculiar to particular tribes, genera, &c. With respect to these, I shall generally refer you to the individuals in which they may be found.
DEFINITIONS.
CORPUS (the Body). The whole crust of the insect; consisting of the Exoderma or external covering, and the Esoderma or internal cuticle that lines it[911]. It is divided into three primary parts, or sections--Caput, Truncus, Abdomen.
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I. CAPUT (The HEAD).
The Head is the anterior section of the body; consisting of a kind of box without suture or segment, which receives the organs of sensation and manducation. It includes the Os, Facies, Subfacies, and Collum.
i. OS (the Mouth). That part of the head which receives and prepares the food for passing into the stomach. It includes the Trophi[912].
1. TROPHI (the Trophi). The different instruments or organs contained in the mouth, or closing it, and employed in manducation or deglutition. They include the Labrum, Labium, Mandibulæ, Maxillæ, Lingua, and Pharynx.
A LABRUM (the Upper-lip). A usually moveable organ; which, terminating the face anteriorly, covers the mouth from above, and is situate between the Mandibulæ[913]. It includes the Appendicula.
a APPENDICULA (the Appendicle). A small piece sometimes appended to the upper-lip[914]. Ex. Halictus ♀ Walck. (Melitta **. b. K.)
B LABIUM (the Under-lip). A moveable organ, often biarticulate, which terminating the surface anteriorly, covers the mouth from beneath, and is situate between the Maxillæ[915]. It includes the Mentum, and Palpi Labiales.
a MENTUM (the Chin). The lower joint of the Labium, where it is jointed; in other cases its base. It is usually seated between the base of the Maxillæ[916].
b PALPI LABIALES (the Labial Feelers). Two jointed sensiferous organs, the use of which is not clearly ascertained, which emerge, one on each side, from the Labium, mostly near its summit[917].
C MANDIBULÆ (the Upper-jaws). Two transverse lateral organs, in most insects used for manducation; generally corneous, moving horizontally, and closing the mouth above, under the Labium[918]. They include the Prostheca, Dentes, and Mola.
a PROSTHECA (the Prostheca). A subcartilaginous process attached to the inner side, near the base, of the Mandibulæ of some Staphylinidæ[919]. Ex. Ocypus similis K., Creophilus maxillosus K., &c.
b DENTES (the Teeth). The terminating points of the Mandibulæ. They include the Incisores, Laniarii, and Molares[920].
A INCISORES (the Cutting-teeth). Teeth somewhat wedge-shaped, externally convex and internally concave[921]. Ex. Gryllotalpa Latr., Gryllus Latr. (Acheta F.), &c. &c.
B LANIARII (the Canine-teeth). Very sharp and usually long conical teeth[922]. Ex. Forficula L., Mantis L., Libellula L.
C MOLARES (the Grinding-teeth). Teeth that terminate in a broad uneven surface, fit for grinding the food[923]. Ex. the herbivorous Orthoptera.
c MOLA (the Mola). A broad, flat, subrotund space, transversely grooved or furrowed, observable on the inner side of some mandibles that have no grinding-teeth at their apex[924]. Ex. Euchlora MacLeay, Anoplognathus Leach, Larva of Lucanus[925].
D MAXILLÆ (the Under-jaws). Two organs moving subhorizontally, fixed on each side at the base of the Labium, and often parallel with it--which in masticating insects seem primarily designed to hold the food[926]. They include the Cardo, Stipes, Lobi, and Palpi maxillares.
a CARDO (the Hinge). A small, transverse, usually triangular, corneous piece, upon which the Maxilla commonly sits[927].
b STIPES (the Stalk). The corneous base of the Maxilla, below the Palpus[928].
c LOBI (the Lobes). The parts of the Maxilla above the Palpus[929]. They include the Lobus superior, the Lobus inferior, and the Ungues.
A LOBUS SUPERIOR (the Upper-lobe). The outer lobe of the Maxilla, incumbent on the inner one. In the Predaceous Beetles this lobe is biarticulate and palpiform[930]; and in Staphylinus olens, &c. it also consists of two joints[931]. It is called the Galea by Fabricius, in Orthoptera, &c.[932]
B LOBUS INFERIOR (the Lower-lobe). The inner lobe of the Maxilla, covered by the outer one[933].
C UNGUES (the Claws). One or more corneous sharp claws which arm the lobes of the Maxilla[934]. In the _Predaceous Beetles_ there is only one terminating the lower lobe, with which, in Cicindela, it articulates; in the Orthoptera and Libellulina there are several.
d PALPI MAXILLARES (the Maxillary Feelers). Two jointed sensiferous organs, the use of which is not clearly ascertained, emerging from an exterior lateral sinus of the Maxilla[935].
E LINGUA (the Tongue). The organ situated within the Labium or emerging from it, by which insects in many cases collect their food and pass it down to the Pharynx, situated at its roots above. It varies considerably in different orders and tribes. In the Orthoptera, Libellulina, &c. it is linguiform, and quite distinct from the Labium[936]; it appears also distinct in the lamellicorn beetles, &c.[937] In many Hymenoptera it emerges from the Labium, and is fitted to collect liquids and pass them downwards[938]. In Formica it appears to be retractile[939]. In a considerable proportion of insects it seems connate with the Labium, and forming its inner surface? According to circumstances it might perhaps be denominated Lingua or Ligula. It includes the Paraglossæ.
a PARAGLOSSÆ (the Paraglossæ). Lateral and often membranous processes observable on each side of the tongue in some Hymenoptera, &c.[940]
F PHARYNX (the Pharynx). The opening into the gullet[941]. It includes the Epipharynx and Hypopharynx.
a EPIPHARYNX (the Epipharynx). A small valve under the Labrum, that in many Hymenoptera closes the Pharynx, and is an appendage of its upper margin[942].
b HYPOPHARYNX (the Hypopharynx). An appendage of the lower margin of the Pharynx, observable in Eucera F.[943]
The seven organs of the mouth above defined, viz. the Labrum, Labium, the two Mandibulæ, the two Maxillæ, and the Lingua, constitute what may be denominated a perfect mouth, peculiar to those insects that masticate their food[944]. In those that take it by suction, the Trophi, to adapt them for that purpose, assume a variety of forms, and should be distinguished by as many appellations. In almost every case, however, the rudiments or representatives of the above organs have been detected by the elaborate researches of that learned and able zoologist, M. Savigny[945]. I shall next subjoin definitions of the principal kinds of suctorious mouths.
2. PROMUSCIS (the Promuscis). The oral instrument of Hemiptera, in which the ordinary Trophi are replaced[946] by a jointed sheath, covered above at the base by the Labrum, without Labella (Liplets) at the end, and containing four long capillary lancets, and a short tongue[947]. It includes the Vagina, and Scalpella.
A VAGINA (the Vagina). The jointed sheath of the Promuscis, representing the Labium in a perfect mouth[948].
B SCALPELLA (the Lancets). Four pieces adapted for perforating the food of the insect, which when united form a tube for suction. The upper pair represent the Manidibulæ[949], and the lower the Maxillæ[950].
3. PROBOSCIS (the Proboscis). The oral instrument of Diptera, in which the ordinary Trophi are replaced by an exarticulate sheath, terminated by Labella, and containing one or more lancets covered by a valve[951]. It includes the Theca, and Haustellum.
A THECA (the Theca). The sheath or case of the Proboscis, representing the Labium in a perfect mouth[952]. It includes the Basis, and Labella.
a BASIS (the Base). The whole lower part of the Theca, from the mouth of the insect as far as the Labella, probably to be regarded as representing the Mentum?
b LABELLA (the Liplets). A pair of tumid lobes, often corrugated and capable of tension and relaxation, which terminate the Theca, and perhaps represent the termination of the Labium[954]?
B HAUSTELLUM (the Haustellum). The instrument of suction contained in the Theca[955]. It includes the Valvula, Cultelli, and Scalpella.
a VALVULA (the Valvule). A corneous piece which covers the instruments of suction above, representing the Labrum in a perfect mouth[956].
b CULTELLI (the Knives). The upper pair of the instruments of suction, which probably make the first incision in the food of the insect; they represent the Mandibulæ of the perfect mouth[957].
c SCALPELLA (the Lancets). A pair of instruments, usually more slender than the Cultelli, which probably enter the veins or sap-vessels, and together with them form a tube for suction[958].
4. ANTLIA (the Antlia). The oral instrument of Lepidoptera, in which the ordinary Trophi are replaced by a spiral, bipartite, tubular machine for suction, with its appendages[959]. It includes the Solenaria, and Fistula.
A SOLENARIA (the Solenaria). The two lateral subcylindrical air-tubes of the Antlia[960].
B FISTULA (the Fistula). The intermediate subquadrangular pipe, formed by the union of the two branches of the Antlia, which conveys the nectar to the Pharynx[961]. These two branches represent the Maxillæ of the perfect mouth.--N. B. M. Savigny discovered the rudiments of the remaining Trophi in this kind of mouth[962].
5. ROSTRULUM (the Rostrulum). The oral instrument of Aphaniptera (Pulex L.), in which the ordinary Trophi are replaced by a bivalve beak, between the valves of which there appear to be three lancets[963]. It includes the Laminæ, Scalpella, and Ligula.
A LAMINÆ (the Laminæ). Two corneous plates which are laterally affixed to the mouth of a flea, probably representing the Mandibulæ of the perfect mouth, which somewhat resemble the beak of a bird[964].
B SCALPELLA (the Lancets). The two upper or outer instruments, probably for making an incision in the skin; these are flat and acute, and seem to represent the Maxillæ of the perfect mouth[965].
C LIGULA (the Ligula). A capillary instrument between the lancets; probably representing the tongue of the perfect mouth[966].
6. ROSTELLUM (the Rostellum). The oral instruments of Pediculus and some other Aptera, in which the ordinary Trophi are replaced by an exarticulate retractile tube, which exerts a retractile siphuncle. It includes the Tubulus and Siphunculus.
A TUBULUS (the Tubulet). The tube or retractile base of the Rostellum.
B SIPHUNCULUS (the Siphuncle). The real instrument of suction, which when unemployed is retracted within the tubulet.
Besides the above variations from the type of what I call a Perfect Mouth, there are others in which the parts of the Trunk appear to aid in the conversion of the food, and become a kind of accessory Labium, Maxilla, &c. Thus in the Myriapods, the anterior pair of legs assume a Maxillary form and office[967]; the Prosternum those of a Labium[968]: in the Arachnida, also, the anterior Coxæ are accessory Maxillæ. In this Class, likewise, as has been more than once observed[969], the representatives of the interior pair of Antennæ of the Crustacea, are thought to assume the form and the functions of suctorious Mandibles[970].
ii. FACIES (the Face). The upper surface of the head[971]. It includes all the parts that lie between its junction with the Prothorax and the Labrum: viz. Nasus, Postnasus, Frons, Vertex, Occiput, Genæ, Tempora, Oculi, Stemmata, and Antennæ.
1. NASUS (the Nose). That portion of the face, often elevated and remarkable, situated between the Labrum, Postnasus, and Genæ, and with which the Labrum articulates; called by Fabricius the Clypeus[972]. It includes the Rhinarium.
A RHINARIUM (the Nostril-piece). The space between the anterior margin of the Nasus and the Labrum, in which, in vertebrate animals, the nostrils are often situated[973].--N. B. This is remarkable in some Lamellicorn beetles, as Anoplognathus Leach. In Necrophorus, and some others, it is membranous.
2. POSTNASUS (the Postnasus). That part of the Face immediately contiguous to the Antennæ, that lies behind the Nasus, when distinctly marked out.--Ex. Sagra, Prosopis.
3. FRONS (the Front). That part of the Face which lies behind the Postnasus, and usually between the posterior part of the eyes. This is sometimes the region of the Stemmata; or they are partly in this or partly in the Vertex[974].
4. VERTEX (the Vertex). The horizontal part of the Facies, next the front, that lies behind the eyes and between the temples[975]. This also is often the region of the Stemmata.
5. OCCIPUT (the Occiput). The back part of the head when it is vertical, or nearly so, to its point of junction with the trunk[976].--Ex. Meloe, Ripiphorus, Hymenoptera, Diptera.
6. GENÆ (the Cheeks). Those parts which lie on the outside of the anterior half of the eyes, and intervene also between them and the Mandibulæ[977].
7. TEMPORA (the Temples). Those parts which lie on the outside of the posterior half of the eyes, between which the Frons and Vertex intervene[978].
8. OCULI (the Eyes). The principal organs of sight, most commonly two in number, placed in the sides of the head. In the majority they are compound, consisting of hexagonal lenses. In the Arachnida they are simple[979].
A CANTHUS (the Canthus). A process of the face, which enters the notch or sinus of the eye[980].--Ex. Scarabæus L., Cerambyx L.
9. STEMMATA (the Eyelets). Two, or more commonly three, convex, crystalline, simple eyes, observable in the Frons or Vertex, or common to both[981].--Ex. Orthoptera, Hemiptera, Hymenoptera.
10. ANTENNÆ (the Antennæ). Two moveable and jointed sensiferous organs, situated in the space between or before the eyes, but in no instance behind them[982]. They include the Torulus, Scapus, Pedicellus, and Clavola.
A TORULUS (the Bed). The cavity or socket in which the base of the Antenna is planted[983].
B SCAPUS (the Scape). The first and in many cases the most conspicuous joint of the Antennæ[984]. It includes the Bulbus.
a BULBUS (the Bulb). The base of the Scapus, by which it inosculates in the Torulus, often subglobose, and looking like a distinct joint[985]. It acts the part of a Rotula, being the pivot upon which the Antenna turns.
C PEDICELLUS (the Pedicel). The second joint of the Antenna[986]: in some insects acting also the part of a Rotula in the socket of the Scapus, to give separate motion to the Clavola.
D CLAVOLA (the Clavolet). The remaining joints of the Antenna taken together[987]. It includes the Capitulum.
a CAPITULUM (the Knob). The last joints of the Clavola when suddenly larger than the rest[988].
iii. SUBFACIES (the Subface). The lower surface or underside of the head[989]. It includes the Lora and Jugulum.
1. LORA (the Lora). A corneous angular machine observable in the mouth of some insects, upon the intermediate angle of which the Mentum sits, and on the lateral ones the Cardines of the Maxillæ; and by means of which the Trophi are pushed forth or retracted[990].--Ex. Hymenoptera.
2. JUGULUM (the Throat). That part of the subface that lies between the temples[991].
iv. COLLUM (the Neck). The constricted posterior part of a pedunculate head, by which it inosculates in the trunk[992]. It includes the Nucha, Gula, and Myoglyphides.
1. NUCHA (the Nape). The upper part of the neck[993]. It includes the Myoglyphides.
A MYOGLYPHIDES (the Muscle-notches). Notches in the posterior margin of the neck, usually two in number, observable in Coleopterous insects, to which the levator muscles are attached[994].
2. GULA (the Gula). The lower part of the neck[995].
v. CEPHALOPHRAGMA (the Cephalophragm). A Y-shaped partition that divides the head internally in Locusta Leach, into two chambers, an anterior and posterior.
II. TRUNCUS (The TRUNK).
The Trunk is the intermediate section of the body, which lies between the Head and the Abdomen[996]. It includes the Manitruncus, and the Alitruncus[997].
/#[6.2] i. MANITRUNCUS (the Manitrunk). The anterior segment of the trunk, in which the head inosculates, or on which it turns[998]. It includes the Prothorax and Antepectus.
1. PROTHORAX (the Prothorax). The upper part or the shield of the manitrunk, in Coleoptera, Orthoptera, &c. called by way of eminence the Thorax[999]. It includes the Ora, Patagia, Umbones, and Phragma.
A ORA (the Ora). The inflexed or inferior lateral margin of the Prothorax, separated in many genera from the Antepectus by a suture[1000].
B PATAGIA (the Patagia). Two corneous scales observable in Lepidoptera, fixed on each side of the trunk, just behind the head, and covered with a long tuft of hair[1001].
C UMBONES (the Bosses). Two moveable bosses surmounted by a spine, with which the Prothorax of the Coleopterous genus Macropus is armed.
D PHRAGMA (the Phragm). The Septum that closes the posterior orifice of the Prothorax in Gryllotalpa Latr.
2. ANTEPECTUS (the Forebreast). The underside or breastplate of the manitrunk, and the bed of the Arms[1002]. It includes the Spiracula Antepectoralia, Prosternum, Antefurca, and Brachia.
A SPIRACULA ANTEPECTORALIA (the Antepectoral Spiracles). A pair of breathing-pores fixed in the membrane that connects the Antepectus with the Medipectus[1003].
B PROSTERNUM (the Forebreast-bone). A longitudinal or other elevation of the Antepectus between the Brachia[1004].
C ANTEFURCA (the Antefurca). An internal vertical process of the Antepectus, consisting usually of two branches, which afford a point of attachment to muscles of the Brachia[1005].
D BRACHIA (the Arms). The first pair of legs of Hexapods, the direction of which is usually towards the head; when spoken of with the other legs, called the Forelegs[1006]. They include the Clavicula, Scapula, Humerus, Cubitus, and Manus.
a CLAVICULA (the Clavicle). The first joint of the Brachium, answering to the Coxa in the legs.
b SCAPULA (the Scapula). The second joint of the Brachium, answering to the Trochanter in the legs.
c HUMERUS (the Humerus). The third and elongated joint of the Brachium, answering to the Femur in the legs.
d CUBITUS (the Cubitus). The fourth and elongated joint, answering to the Tibia in the legs. It includes the Coronula and Calcaria. . A CORONULA (the Coronula). A coronet or semicoronet of spines, observable at the apex of the Cubitus or Tibia of some insects.--Ex. Dilophus Latr., Fulgora L.
B CALCARIA (the Spurs). See the definition under _Pedes Postici_. They include the Velum.
a VELUM (the Velum). A membrane attached to the inner side of the cubital spur in Apis L.[1007]
e MANUS (the Hand). The terminal jointed portion of the Brachium, answering to the Tarsus in the legs[1008]. It includes the Pulvilli, Palma, and Digitus.
f PULVILLI (the Pulvilli). See definition under Pedes Postici.
g PALMA (the Palm). The first joint of the Manus, when longer and broader than the subsequent ones, or otherwise remarkable; answering to the Planta in the legs[1009].
A DIGITUS (the Finger). See definition under Pedes Postici. It includes the Ungula.
a UNGULA (the Claw-joint). See definition under _Pedes Postici_. It includes the Pollex, Unguiculi, and Palmula.
α POLLEX (the Thumb). A small accessory joint, attached to the Ungula of the Manus in Mantis F.
β UNGUICULI (the Claws). See definition under Pedes Postici.
γ PALMULA (the Palmlet). A minute accessory joint between the claws, answering to the Plantula in the legs. It includes the Pseudonychia.
* PSEUDONYCHIA (the Spurious Claws). See definition under Pedes Postici.
ii. ALITRUNCUS (the Alitrunk). The posterior segment of the trunk to which the abdomen is affixed, and which bears the legs and wings[1010]. It includes the Mesothorax and Medipectus, and the Metathorax and Postpectus.
1. MESOTHORAX (the Mesothorax). That segment of the alitrunk which bears the Elytra, or the anterior pair of wings, and the intermediate pair of legs[1011]. It includes the Collare, Prophragma, Dorsolum, Scutellum, Frænum, and Pnystega.
A COLLARE (the Collar). The first or anterior piece of the Mesothorax. In most insects that have a conspicuous Prothorax, as the Coleoptera, this piece appears scarcely to have a representative; but in the Libellulina it co-exists with it, and is more conspicuous[1012]. It is particularly remarkable in Hymenoptera and Diptera.
B PROPHRAGMA (the Prophragm). A partition of an elastic substance, rather horny, connected posteriorly with the Dorsolum, which passes down into the anterior cavity of the alitrunk, of which it forms the upper separation from that of the manitrunk. It affords a point of attachment to several muscles of the wings, &c.[1013]
C DORSOLUM (the Dorslet). The piece which lies between the Collare and Scutellum, to which the prophragm is anteriorly attached, and which bears the upper or anterior organs of flight[1014]. It includes the Pteropega, Elytra, Tegmina, Hemelytra, Alæ Superiores, and Tegulæ.
a PTEROPEGA (the Wing-socket). The space in which the organs for flight are planted. That for the secondary or under-wings is in the Metathorax[1015].
b ELYTRA (the Elytra). The upper organs 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 the Axis, Sutura, Epipleura, Alula, and Hypoderma, and are peculiar to the Coleoptera and Dermaptera.
A AXIS (the Axis). A small, prominent, irregular process of the base of the Elytrum, upon which it turns, and by the intervention of which it is affixed to the Dorsolum, in the anterior wing-socket[1017].
B SUTURA (the Suture). The conflux of the sutural or inner margins of the two Elytra, where when closed they unite longitudinally[1018].
C EPIPLEURA (the Epipleura). The inflexed accessory margin observable underneath in many Elytra, which covers the sides of the alitrunk and abdomen[1019].
D ALULA (the Winglet). A small, membranous, wing-like appendage, attached to the Elytrum on one side and the Frænum on 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 in Blatta and the Diptera.
E HYPODERMA (the Hypoderma). The skin, in some species beautifully coloured, that lines the Elytra[1021]. N. B. This skin is also found in some Hemelytra, but not in Tegmina.
c TEGMINA (the Tegmina). 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].
d HEMELYTRA (the Hemelytra). The upper organs of flight, when they are corneous or coriaceous at the base and membranous at the apex[1024].--Ex. The heteropterous Hemiptera. They include the Corium and Membrana.
A CORIUM (the Corium). The corneous or coriaceous part of the Hemelytrum[1025].
B MEMBRANA (the Membrane). The membranous part of the same[1026].
e ALÆ SUPERIORES vel PRIMARIÆ (the Upper or Primary Wings). The upper or anterior organs of flight when formed of membrane, or of the same substance with the under-wings[1027]. They include the Axes, Areæ, Areolæ, Neuræ, Stigma, Parastigma, and Lobuli.
A AXES (the Axes). Several osseous or horny pieces, by which the wing is connected with the Dorsolum[1028]. One usually to each area.
B AREÆ (the Areas). The larger longitudinal spaces into which the wing may be divided[1029]. They include the _Area Costalis_, Intermedia, and Analis.
a AREA COSTALIS (the Costal Area). That part of the wing lying between the anterior margin and the post-costal nervure[1030]. In Hymenoptera and Diptera it includes all the space bounded by the nervures that spring from the postcostal.
b AREA INTERMEDIA (the Intermediate Area). That part of the wing lying between the costal area and the interno-medial nervure, in Diptera; or the Anal in Orthoptera, Hemiptera, Hymenoptera, &c.[1031]
c AREA ANALIS (the Anal Area). All that part of the wing which in Diptera lies between the internomedial nervure; or in Orthoptera, &c. between the anal nervure and the posterior margin[1032].
C AREOLÆ (the Areolets). The smaller spaces into which the wing is divided by the nervures. They include the _Areolæ Basilares_, Mediæ, and Apicales.
a AREOLÆ BASILARES (the Basal Areolets). The parallel areolets of the base of the wing[1033].
b AREOLÆ MEDIÆ (the Middle Areolets). The areolets of the wing that lie between the basal areolets and the apical[1034].
c AREOLÆ APICALES (the Apical Areolets). Those areolets of the wing that terminate in or very near the apex[1035].
D NEURÆ (the Nervures). Corneous tubes, for expanding the wing and keeping it tense, and to afford protection to the air-vessels--commonly called the Nerves. They include the Neura Costalis, Postcostalis, Mediastina, Externo-media, Interno-media, Analis, Axillaris, and Spuria.
a NEURA COSTALIS (the Costal Nervure). The first principal nervure of the wing, close to or forming the anterior margin in Lepidoptera, Hymenoptera, and Diptera; but sometimes remote from it in Tegmina[1036]. It includes the Phialum and Hamus.
α PHIALUM (the Phial). 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 in Coleoptera[1037].
β HAMUS (the Hook). A Hook fixed to the Costal Nervure, near its base on the under-side, in the wings of some Lepidoptera, in which the tendon runs[1038].
b NEURA POSTCOSTALIS (the Postcostal Nervure). The second principal, and often strongest, nervure of the wing[1039]. It includes the Neuræ Subcostales.
α NEURÆ SUBCOSTALES (the Subcostal Nervures). Nervures springing from the under-side of the postcostal nervure, or from each other; called the first, second, third, &c. in the order of their occurrence[1040].
c NEURA MEDIASTINA (Mediastinal Nervure). A usually slender nervure, springing from near the base of the postcostal; between which and the costal it intervenes. In the Lepidoptera Diurna, however, it is often a strong nervure[1041].
d NEURA EXTERNO-MEDIA (the Externo-medial Nervure). The third principal nervure of the wing[1042]. It includes the Neura Subexterno-media.
α NEURA SUBEXTERNO-MEDIA (the Subexterno-medial Nervure). A nervure that in some cases intervenes between the externo-medial and interno-medial[1043].
e NEURA INTERNO-MEDIA (the Interno-medial Nervure). The fourth principal nervure[1044]. It includes the _Neura Subinterno-media_.
α NEURA SUBINTERNO-MEDIA (the Subinterno-medial Nervure). A nervure that sometimes intervenes between the externo-medial and the anal[1045].
f NEURA ANALIS (the Anal Nervure). The principal nervure nearest the interior or posterior margin, with which it includes a space often subtriangular, traversed in most Diptera and many Hymenoptera by another nervure; and in many Tegmina and Hemelytra by 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.
g NEURA AXILLARIS (the Axillary Nervure). The short nervure, where there is only one, intervening between the anal nervure and the interior margin; replaced in some Muscidæ by a spurious nervure[1047].
h NEURÆ SPURIÆ (the Spurious Nervures). Very obsolete nervures, sometimes found in addition to those usually occurring; as in Syrphus[1048].
E STIGMA (the Stigma). 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].
F PARASTIGMA (the Parastigma). A corneous spot between the costal and postcostal nervures, distinct from the Stigma observable in the Libellulina.
G LOBULI (Lobuli). One or more rounded portions of the base of the wing, separated from the rest by fissures peculiar to the Muscidæ, and the under-wings of some Hymenoptera[1050].
f TEGULÆ (the Tegulæ). Small corneous concavo-convex scales, which in many Orders, particularly Hymenoptera, cover and defend the base of the Upper-Wings[1051].
D SCUTELLUM (the Scutellum). A piece, usually triangular, which follows the Dorsolum; and in Coleoptera is often only a continuation of it--placed between the base of the Elytra or upper-wings[1052].
E FRÆNUM (the Frænum). A piece that lies under the lateral margin of the Scutellum and Dorsolum, 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].
F PNYSTEGA (the Pnystega). A corneous scale or plate, which covers certain pneumatic vessels, usually supported by the Scapularia, in Libellulina, &c. becoming dorsal[1054].
2. MEDIPECTUS (the Mid-breast). The underside of the first segment of the alitrunk[1055]. It includes the Peristethium, Scapularia, Mesosternum, Medifurca, and Pedes Intermedii.
A PERISTETHIUM (the Peristethium). The anterior piece of the Medipectus, which intervenes between the Brachia and mid-legs[1056].
B SCAPULARIA (the Scapulars). Two pieces, one on each side the Medipectus, which succeed the Peristethium, and lie between the midlegs and the Pteropega or wing-socket[1057]. It includes the Spiracula Scapularia.
a. SPIRACULA SCAPULARIA (the Scapular Spiracles). Two spiracles observable, one in each scapular, in Acrida laurifolia, &c.
C MESOSTERNUM (the Mid-breastbone). The elevated and central part of the Medipectus, between the midlegs, often terminating anteriorly in a mucro; sometimes, as in Elater, in a cavity, receiving the mucro of the Prosternum[1058].
D MEDIFURCA (the Medifurca). A branching vertical process of the Endosternum, which serves as the point of attachment to the muscles that move the midlegs[1059].
E PEDES INTERMEDII (the Mid-legs). The intermediate pair of legs, consisting of the same parts as the posterior legs[1060].
3. METATHORAX (the Metathorax). The posterior segment of the Alitruncus[1061]. It includes the Mesophragma, Postdorsolum, Postscutellum, Postfrænum, Pleuræ, and Metaphragma.
a MESOPHRAGMA (the Mesophragm). A partition of a firm consistence, connected by its posterior margin with the Postdorsolum, 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 anterior cavity of the alitrunk, and with the metaphragm it forms the posterior cavity.
b POSTDORSOLUM (the Postdorsolum). The middle-piece between the mesophragm and the Postscutellum. In Coleoptera it consists of a tense elastic membrane, which is quite covered by the Mesothorax[1063].
c POSTSCUTELLUM (the Postscutellum). A narrow channel running from the Dorsolum to the Abdomen in Coleoptera, forming an isosceles triangle reversed. In other orders it is either a triangular elevation of the middle of the posterior part of the Postdorsolum, or a distinct triangular piece[1064].
d POSTFRÆNUM (the Postfrænum). In Coleoptera the part of the Metathorax in which the Postscutellum lies, 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 the Postscutellum and the Abdomen; 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].
e PLEURÆ (the Pleuræ). The space behind the scapulars, on which the lower organs of flight are fixed[1066]. They include the Alæ Inferiores.
A ALÆ INFERIORES (the Under-wings). The lower or secondary pair of organs for flight[1067]. They include the Commissura, Tendo, Hamuli, Pterygium, Alula, and Halteres.
a COMMISSURA (the Commissura). A joint in the costal nervure of the wings of Coleoptera, where they bend to take a transverse fold[1068].
b TENDO (the Tendon). A strong bristle, or bristles observable at the base underneath in the under-wings of many Lepidoptera, which plays in the Hamus of the upper-wings[1069].
c HAMULI (the Hooklets). Very minute hooks in the middle of the anterior margin, observable in some Hymenoptera, by which the under-wing is fixed to the upper, to cause both to act as one organ in flight[1070].
d PTERYGIUM (the Pterygium). In under-wings this is a small wing-like appendage, fixed at the base of the wing in some Lepidoptera[1071].
e ALULA (the Winglet). A small concavo-convex scarious appendage, fixed behind the wings at their base, in many Diptera[1072].
f HALTERES (the Poisers). Small capitate processes or organs, observable under the wings of Diptera, attended by a spiracle[1073].
B METAPNYSTEGA (the Metapnystega). A corneous scale or lamina that covers the pneumatic organs in the Metathorax, situated sometimes in the Pleuræ, as in the Coleoptera; at others in the Postfrænum, as in Tenthredo L.; and sometimes, as in the Libellulina, between that part and the abdomen[1074].
C METAPHRAGMA (the Metaphragm). A nearly vertical septum or partition, attached behind to the Postfrænum, and usually deeply cleft at its apex in Coleoptera, of a rather horny consistence, which forms the upper separation of the second cavity of the Alitrunk from that of the Abdomen[1075]. It affords a point of attachment for many muscles of both alitrunk and abdomen. It includes the Septula.
a SEPTULA (the Septula). 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 (the Postpectus). The underside of the second segment of the alitrunk[1077]. It includes the Mesostethium, Parapleuræ, Metasternum, Postfurca, Opercula, and Pedes Postici.
A MESOSTETHIUM (the Mesostethium). A central piece between the intermediate and posterior legs, and bounded laterally in Coleoptera by the Parapleuræ--along the middle of which, where it exists, the Metasternum runs[1078].
B PARAPLEURÆ (the Parapleuræ). Two pieces, one on each side of the Postpectus, included between the Scapularia, Mesostethium, and Pleuræ[1079]. They include the Spiracula Parapleuritica.
a SPIRACULA PARAPLEURITICA (the Parapleuritic Spiracles). Two spiracles, one in each of the Parapleuræ of Tetyra[1080].
C METASTERNUM (the Metasternum). The central and often elevated part of the Mesostethium. Its anterior mucro, in Coleoptera, often meets the posterior one of the Mesosternum, and sometimes appears to form one piece with it, as in Hydrophilus, and many Lamellicorn beetles. Sometimes, as in Cetonia vitticollis, it even passes between the arms, and covers the Prosternum, or supplies its place. Behind, it often terminates in a bifid mucro. It is not present in many Orders: as in the Hymenoptera, Diptera, &c.[1081] It includes the Pectines.
a PECTINES (the Pectines). Two moveable processes, fixed one on each side by its base below the posterior legs to the Metasternum in Scorpio: on the lower side is fixed a series of parallel biarticulate processes, resembling the teeth of a comb[1082].
D POSTFURCA (the Postfurca). A process of the Endosternum, terminating in three subhorizontal acute branches, resembling the letter Y, and forming an acute angle with the Endosternum, to which the muscles that move the hind-legs, &c. are affixed[1083].
E OPERCULA (the Opercula). Plates that cover the vocal spiracles in humming insects; and likewise two large cartilaginous plates fixed to the posterior part of the Postpectus, which cover the Tympana in male Tettigonia F.[1084] Perhaps these may be regarded as a kind of Metapnystega in a new situation.
F PEDES POSTICI (the Hind-legs). The pair of legs affixed to the postpectus[1085]. They include, the Acetabulum, Coxa, Trochanter, Femur, Tibia, and Tarsus.
a ACETABULUM (the Socket). The socket in the Postpectus in which the leg is planted[1086]. It includes the Pessella.
A PESSELLA (the Pessella). Two little acute processes, fixed one in each, in the socket of the hind-legs in male Tettigoniæ, which appear designed to keep down the Opercula[1087].
b COXA (the Hip). The first joint of the leg which plays in the socket[1088].
c TROCHANTER (the Trochanter). The second joint of the leg, by which the thigh inosculates in the Coxa. It appears to have no motion separate from that of the thigh. It is sometimes biarticulate[1089].
d FEMUR (the Thigh). The third joint of the leg, long and usually compressed[1090]. It includes the Gonytheca.
A GONYTHECA (the Knee-pan). A concavity at the apex of the thigh, underneath, to receive the base of the Tibia[1091].
e TIBIA (the Shank). The fourth joint of the leg, very long, and usually triquetrous[1092]. It includes the Epicnemis, Molula, Talus, Calcaria, and Coronula.
A EPICNEMIS (the Epicnemis). An accessory joint at the base of the Tibia in many Arachnida, which does not appear to have separate motion[1093].
B MOLULA (the Knee-ball). The convex and sometimes bent head of the Tibia, armed with a horny process on each side, by which it is attached to the thigh[1094].
C TALUS (the Ankle). The apex of the Tibia, where it is united to the Tarsus[1095].
D CALCARIA (the Spurs). One, two, or more moveable spines, inserted usually at the apex of the Tibia; and in many Carabi L., Lepidoptera L., and Trichoptera K., in the middle also. They may be regarded as a kind of fingers auxiliary to the Tarsus, and furnish often an important character in the discrimination of genera[1096].
E CORONULA (the Coronula). A coronet or semicoronet of fixed spines observable at the apex of the posterior Tibia in Fulgora candelaria, &c.
f TARSUS (the Tarsus). The fifth principal portion of the legs; consisting in the majority of insects of 1-5 joints, but in the Phalangidæ of sometimes as many as 50[1097]. It includes the Planta, Digitus, and Solea.
A PLANTA (the Instep). The first joint of the Tarsus is so called when it is remarkably long and broad[1098]. It includes the Calx.
a CALX (the Heel). The curving part of the Planta, by which it inosculates with the Tibia.
B DIGITUS (the Toe). The remaining joints of the Tarsus taken together[1099]. It includes the Allux and Ungula.
a ALLUX (the Toe-ball). The last joint but one of the Tarsus, when remarkable, as in Rhyncophorous beetles (Curculio L.)[1100].
b UNGULA (the Claw-joint). The last joint of the Tarsus, which bears the claws[1101]. It includes the Arthrium, Unguiculi, and Plantula.
α ARTHRIUM (the Arthrium). A very minute joint at the base of the claw-joint, in most Tetramerous and Trimerous beetles[1102].
β UNGUICULI (the Claws). One or two pair of moveable incurved claws, which usually arm the apex of the Ungula[1103].
γ PLANTULA (the Plantula). A minute accessory joint, sometimes attached within the claws to the apex of the Ungula[1104]. Ex. The Lucanidæ. It includes the Pseudonychia.
* PSEUDONYCHIA (the Spurious Claws). Two stiff clawlike bristles, that terminate the Plantula[1105].
C SOLEA (the Sole). The underside of the Tarsus[1106]. It includes the Pulvilli.
a PULVILLI (the Pulvilli). 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 the Manus or Tarsus, and sometimes even of the ends of the Calcaria, as in Cimbex; which act so as to produce a vacuum, and enable the animal to suspend itself, or walk against gravity[1107]. Ex. Timarcha, Buprestis, Priocera K., the Gryllina, Muscidæ, &c.
III. ABDOMEN (the Abdomen).
The Abdomen is the third or posterior section of the body which follows the Truncus[1108]. It includes the Tergum, Venter, Petiolus, Cauda, and Anus.
i. TERGUM (the Tergum). The upper or supine surface of the abdomen[1109]. It includes the Segmenta Dorsalia, and Pulmonaria.
1. SEGMENTA DORSALIA (the Dorsal Segments). Transverse segments of the back, the sides of which often lap over and cover those of the ventral segments[1110].
2. PULMONARIA (the Pulmonary 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 the Spiracula Dorsalia.
a SPIRACULA DORSALIA (the Dorsal Spiracles). Lateral breathing-pores observable in the dorsal segments, often covered by the preceding segment[1112].
ii. VENTER (the Belly). The lower or prone part of the abdomen[1113]. It includes the Hypochondria, Epigastrium[1114], Segmenta Ventralia, and Elastes.
1. HYPOCHONDRIA (the Hypochondria). Two portions of segments, one on each side; which in some genera[1115] (Carabus L., &c.) intervene between the first intire ventral segment and the posterior part of the Postpectus.
2. EPIGASTRIUM (the Epigastrium). The first intire ventral segment[1116]. It includes the Mucro and Tympana.
A MUCRO (the Mucro). The central posterior point of the Epigastrium observable in many of the Orders, which reposes between the posterior legs; and, according to M. Chabrier, is useful to the insect during flight[1117].
B TYMPANA (the Drums). Two deep cavities, containing a complex machinery on each side of the Epigastrium in male Tettigoniæ, which are the instruments of sound[1118].
3. SEGMENTA VENTRALIA (the Ventral Segments). Transverse sections of the belly[1119]. In Elytrophorous insects they are usually of a firmer consistence than those of the back. They include the Spiracula Ventralia.
A SPIRACULA VENTRALIA (the Ventral Spiracles).--Breathing-pores observable in some genera in the intermediate ventral segments, one on each side[1120]. Ex. Dynastes Aloeus, &c.
4. ELASTES (the Elastes). The elastic organs on the ventral segments of Machilis polypoda which assist this insect in leaping.
iii. PETIOLUS (the Footstalk). A slender part by which the abdomen of many Hymenoptera is united to the trunk, in some genera very long, in others very short, and in others wanting[1121]. It includes the Funiculus, Foramen, Squama, and Nodus.
1. FUNICULUS (the Funiculus). A small cartilaginous cord, passing through a minute orifice of the Postfrænum, 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 (the Foramen). The orifice in the abdomen, through which the above cord passes[1123].
3. SQUAMA (the Scale). A vertical flat scale, observable on the footstalk of the genus Formica, &c.[1124]
4. NODI (the Knots). One or more subrotund protuberances of the footstalk in the genus Myrmica[1125].
iv. CAUDA (the Tail). Where the abdomen grows suddenly slenderer, and terminates in a long jointed tail, as in Scorpio and Panorpa[1126]. It includes the Centris.
1. CENTRIS (the Centris). The last inflated joint of the tail, terminating in the Sting.
v. ANUS (the Anus). The termination of the abdomen, consisting of the two last segments. It includes the Podex, Hypopygium, Culus, Ovipositor, and Appendices.
1. PODEX (the Podex). The last dorsal segment of the abdomen[1127].
2. HYPOPYGIUM (the Hypopygium). The last ventral segment of the abdomen[1128].
3. CULUS (the Culus). The orifice at the end of the anus.
4. OVIPOSITOR (the Ovipositor). 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 the Aculeus[1129]. It includes the Unci, Tubulus, Valvæ, Vaginula, and Terebellæ.
A UNCI (the Unci). Two pair of robust organs, the upper incurved and the lower recurved, with which the anus of Locusta Leach is furnished[1130].
B TUBULUS (the Tubulus). A tubular ovipositor, consisting of several pieces often retractile within each other, like the tubes of a telescope[1131].
C VALVÆ (the Valves). Two lateral laminæ, often coriaceous, by which the ovipositor when unemployed is covered[1132].
D VAGINULA (the Sheath). A corneous case, with two grooves, in which the Terebella or Spicula play[1133].
E TEREBELLÆ (the Terebellæ). 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 (the Sting). The above instrument, when fitted for an offensive weapon[1135]. It includes, besides the Valvæ and Vaginula before defined, the Spicula.
A SPICULA (the Darts). The proper stings which inflict the wound: retractile within the sheath, externally serrulate at the apex[1136]. They include the Retinaculum.
a RETINACULUM (the Retinaculum). 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 (the Appendages). Other instruments and organs, with which the anus of various insects is furnished. They include--the Forceps, Forfex, Furca, Styli, Foliola, Flosculus, Caudulæ, Fila, Mammulæ, Papillæ, and Siphonuli.
1. FORCEPS (the Forceps). A pair of anal organs that open and shut transversely, and meet at their inner margin, or at the apex. Ex. Forficula.
2. FORFEX (the Forfex). A pair of anal organs, which open or shut transversely, and cross each other[1138]. Ex. Male of Raphidia Ophiopsis.
3. FURCA (the Fork). An inflected elastic anal organ, ending in a fork, by which the animal is enabled to leap[1139]. Ex. Podura.
4. STYLI (the Styles). Rigid, exarticulate, long and narrow anal organs[1140]. Ex. Staphylinus.
5. FOLIOLA (the Leaflets). Rigid, exarticulate, dilated, leaf-like anal organs[1141]. Ex. Libellulina.
6. FLOSCULUS (the Floret). A small, tubular, lunulate anal organ, with a central style[1142]. Fulgora candelaria, &c.
7. CERCI (the Cerci). Two short, flattish, sublanceolate, jointed, lateral anal organs[1143]. Ex. Blatta.--N.B. Analogous organs are observable in the Gryllina, but usually conical and without joints[1144]. In Gryllus Latr. they are setiform[1145].
8. CAUDULÆ (the Caudulæ). Two or more slender, filiform or setaceous, jointed, flexile anal organs[1146]. Ex. Lepisma, Machilis, Ephemera.
9. FILA (the Threads). Two exarticulate, slender, filiform anal organs[1147]. Ex. Machilis.
10. MAMMULÆ (the Mammulæ). Anal protuberances, containing instruments for spinning web[1148]. Ex. Araneidæ. They include the Fusi.
11. FUSI (the Spinners). Organs, consisting of two retractile pieces, issuing from the Mammulæ, and rendering the threads[1149].
12. SIPHONULI (the Siphonets). Truncated, fistular, setiform anal organs, emitting a saccharine fluid[1150]. Ex. Aphis.
You will observe, that when the whole upper-side of the Truncus is spoken of, it is called the Thorax; and as in Coleoptera, and some other Orders, the whole of the Mesothorax except the Scutellum is covered by the Thorax, and the whole of the Metathorax by the Mesothorax and Elytra--the Thoracic shield, may without danger of mistake be denominated the Thorax, as it has always been. When the whole under-side of the Trunk is spoken of, it is called the Pectus. When the three Sternums are spoken of together, they may be called the Sternum; and the whole interior elevation of the Pectus may be called the Endosternum.
FOOTNOTES:
[903] Lamarck Hist. Nat. des Anim. sans Vertèbr. i. 311, 214.Return to passage
[904] Ibid. 162. Compare the Systême des Anim. sans Vertèbr. of the same author, p. 12--.Return to passage
[905] The doctrine of Epicurus--that the Deity concerns not himself with the affairs of the world or its inhabitants, which, as Cicero has judiciously observed (De Nat. Deor. 1. 1. ad calcem), while it acknowledges a God in words, denies him in reality; has furnished the original stock upon which most of these bitter fruits of modern infidelity are grafted. Nature, in the eyes of a large proportion of the enemies of Revelation, occupies the place and does the work of its Great Author. Thus Hume, when he writes against miracles, appears to think that the Deity has delegated some or all of his powers to nature, and will not interfere with that trust. Essays, ii. 75--. And to name no more, Lamarck, treading in some measure in the steps of Robinet (who supposes that all the links of the animal kingdom, in which nature gradually ascends from low to high, were experiments in her progress towards her great and ultimate aim--the formation of man. Barclay On Organization, &c. 263), thus states his opinion: "La nature, dans toutes ses opérations, ne pouvant procéder que graduellement, n'a pu produire tous les animaux à-la-fois: elle n'a d'abord formé que les plus simples; et passant de ceux-ci jusques aux plus composés, elle a établi successivement en eux différens systêmes d'organes particuliers, les a multipliés, en a augmenté de plus en plus l'énergie, et, les cumulant dans les plus parfaits, elle a fait exister tous les animaux connus avec l'organisation et les facultés que nous leur observons." (Anim. sans Vertèbr. i. 123.) Thus denying to the Creator the glory of forming those works of creation, the animal and vegetable kingdom (for he assigns to both the same origin, Ibid. 83), in which his glorious attributes are most conspicuously manifested; and ascribing them to nature, or a certain order of things, as he defines it (214)--a blind power, that operates necessarily (311); which he admits, however, to be the product of the will of the Supreme Being (216). It is remarkable, that in his earlier works, in which he broaches a similar opinion, we find no mention of a Supreme Being. (See his Systême des Animaux sans Vertèbres, Discours d'Ouverture.) Thus we may say that, like his forerunner Epicurus, Re tollit, dum oratione relinquit Deum. But though he ascribes all to nature; yet as the immediate cause of all the animal forms, he refers to the local circumstances, wants, and habits of individual animals themselves; these he regards as the modifiers of their organization and structure (162). To show the absurd nonplus to which this his favourite theory has reduced him, it will only be necessary to mention the individual instances which in different works he adduces to exemplify it. In his Systême, he supposes that the web-footed birds (Anseres) acquired their natatory feet by frequently separating their toes as far as possible from each other in their efforts to swim. Thus the skin that unites these toes at their base contracted a habit of stretching itself; and thus in time the web-foot of the duck and the goose were produced. The waders (Grallæ), which, in order to procure their food, must stand in the water, but do not love to swim, from their constant efforts to keep their bodies from submersion, were in the habit of always stretching their legs with this view, till they grew long enough to save them the trouble!!! (13--). How the poor birds escaped drowning before they had got their web feet and long legs, the author does not inform us. In another work, which I have not now by me, I recollect he attributes the long neck of the camelopard to its efforts to reach the boughs of the mimosa, which, after the lapse of a few thousand years, it at length accomplished!!! In his last work, he selects as an example one of the Molluscæ, which, as it moved along, felt an inclination to explore by means of touch the bodies in its path: for this purpose it caused the nervous and other fluids to move in masses successively to certain points of its head, and thus in process of time it acquired its horns or tentacula!! Anim. sans Vertèbr. i. 188. It is grievous that this eminent zoologist, who in other respects stands at the head of his science, should patronize notions so confessedly absurd and childish.Return to passage
[906] Lyonnet Traité, &c. Pref. xxii. Want of due encouragement, it is to be feared, caused the abortion of these valuable treatises. The MSS. are, I believe, still in existence. It would probably answer now to publish them.Return to passage
[907] See above, p. 52--.Return to passage
[908] See above, p. 43--.Return to passage
[909] There are certain processes which are a continuation of the internal surface of the crust; and serve, as well as the rest of it, for points of attachment to the muscles: these, though completely internal, must be considered as parts of the external skeleton.Return to passage
[910] See above, p. 28--.Return to passage
[911] The crust which covers the body of insects is lined internally with a kind of fibrous cuticle. Query, Whether in any degree analogous to the Periosteum of Vertebrate animals?Return to passage
[912] We employ this term instead of Instrumenta Cibaria F., to avoid circumlocution.Return to passage
[913] PLATES VI. VII. &c. a´, and XXVI. FIG. 30-33.Return to passage
[914] Ibid. FIG. 30. Mon. Ap. Angl. i. 139. Melitta **. b. t. ii. f. 4, 5.Return to passage
[915] PLATES VI. VII. &c. and XXVI. FIG. 23-29. b´.Return to passage
[916] PLATES VI. and VII. a´´, and XXVI. FIG. 34, 35.Return to passage
The part in this work regarded as the mentum, does not in all cases accord with what MM. Latreille, Savigny, &c. have regarded as entitled to that denomination. Thus in Hymenoptera, their Mentum is what we term the Labium, while our Mentum is the small piece upon which that part sits (PLATE VII. FIG. 3. a´´). This is called the Fulcrum in Mon. Ap. Angl. (See i. Explan. of the Plates.) Our Mentum may generally be known by its situation between the hinges and base of the Maxillæ.
[917] PLATES VI., VII., and XXVI. b´´.Return to passage
[918] Ibid.Return to passage
[919] PLATE XIII. FIG. 7. c´´.Return to passage
[920] Marcel de Serres Comparaison des Organes de la Mastication des Orthoptères. 7. Ann. du Mus. 11.Return to passage
[921] PLATE VI. FIG. 6. c´, a´´´. and XIII. FIG. 5. a´´´.Return to passage
[922] PLATE VI. FIG. 12. b´´´. and XIII. FIG. 5. b´´´.Return to passage
[923] PLATE XXVI. FIG. 16. c´´´.Return to passage
[924] Ibid. FIG. 20. d´´´.Return to passage
[925] Cuv. Anat. Comp. iii. 322--.Return to passage
[926] PLATES VI. VII. d´. and XXVI. FIG. 9-15.Return to passage
[927] Ibid. c´´.Return to passage
[928] Ibid. f´´.Return to passage
[929] Ibid. and XXVI. FIG. 13-15.Return to passage
[930] PLATE VI. FIG. 3. d´´´.Return to passage
[931] PLATE XXVI. FIG. 11. d´´´.Return to passage
[932] PLATE VI. FIG. 6, 12. d´´´.Return to passage
[933] Ibid. FIG. 3, 6, 12. and XXVI. FIG. 9, 10. e´´´.Return to passage
[934] Ibid. VI. FIG. 3, 12. f´´´.Return to passage
[935] PLATES VI. VII. h´´. XIII. FIG. 1-4, 8. h´´. and XXVI. FIG. 1-8.Return to passage
[936] PLATE VI. FIG. 6, 12. e´.Return to passage
[937] PLATE XXVI. FIG. 26, 29. e´.Return to passage
[938] PLATE VII. FIG. 2, 3, e´.--What is here called the Lingua in Hymenoptera has been usually regarded as the Labium; but surely that organ which collects, and as it were laps the honey, and passes it down to the Pharynx, is properly to be considered as the tongue. The Labium itself appears to be represented by what has been called the Mentum, and the true Mentum, as was lately observed, is at the base of the part last mentioned, in the usual situation of that piece. This, though long since noticed (Kirby Mon. Ap. Angl. i. 103--), has not been much attended to by modern entomologists.Return to passage
[939] Huber Fourmis, 4--.Return to passage
[940] PLATE VII. FIG. 2, 3. and XXVI. FIG. 28. i´´.Return to passage
[941] PLATE VII. FIG. 14. f´.Return to passage
[942] Ibid. FIG. 2. k´´. This is M. Savigny's name for this part. It has also been called Epiglossa. Latreille Organisation Extérieure des Insectes, 185.Return to passage
[943] Vide Savigny Mém. sur les Anim. sans Vertèbr. I. i. 12--.Return to passage
[944] The majority of Hymenopterous insects, though they have the ordinary Trophi, are not masticators, using their mandibulæ only for purposes connected with their economy.Return to passage
[945] See his Mémoires sur les Animaux sans Vertèbres, I. i.Return to passage
[946] I have used this word here and on a former occasion (see above, p. 29), perhaps not with strict propriety, in the sense of the French word remplacer, for which we seem to have no single corresponding word in our language.Return to passage
[947] PLATE VI. FIG. 7-9.Return to passage
[948] PLATE VI. FIG. 7, 9. b´.Return to passage
[949] Ibid. c´.Return to passage
[950] Ibid. d´.Return to passage
[951] Ibid. VII. FIG. 5, 6.Return to passage
[952] Ibid. b´.Return to passage
[953] Ibid. FIG. 6. b´.
[954] Ibid. a. The Labella have been usually thought confined, or nearly so, to the genus Musca L.; but they may be traced in all genuine Diptera, i. e. excluding Hippobosca L.Return to passage
[955] PLATE VII. FIG. 5. a´, c´, d´.Return to passage
[956] PLATE VII. FIG. 5, 6. a´.Return to passage
[957] Ibid. c´.Return to passage
[958] Ibid. d´. It has not yet been satisfactorily ascertained, whether all the ordinary Trophi are represented in every Dipterous mouth, the number of the lancets seeming in some cases to vary.Return to passage
[959] PLATE VI. FIG. 13.Return to passage
[960] Ibid. a.Return to passage
[961] Ibid. b.Return to passage
[962] Ibid. Labrum a´; Mandibulæ c´; Maxillary Palpus h´´.Return to passage
[963] PLATE VII. FIG. 8.Return to passage
[964] Ibid. c´.Return to passage
[965] Ibid. d´. Maxillary Palpi h´´.Return to passage
[966] Ibid. e´.Return to passage
[967] PLATE VII. FIG. 11, 13. f´.Return to passage
[968] Ibid. FIG. 11. d´.Return to passage
[969] See above, p. 18, &c.Return to passage
[970] PLATE VI. FIG. 10. c´.Return to passage
[971] PLATE VI. FIG. 1, 4, 10. â.Return to passage
[972] Ibid. a.Return to passage
[973] Ibid. g´.Return to passage
[974] PLATE VI. c.Return to passage
[975] Ibid. d.Return to passage
[976] Ibid. e.Return to passage
[977] Ibid. f.Return to passage
[978] Ibid. g.Return to passage
[979] PLATES VI. VII. and XXVI. h.Return to passage
[980] PLATE VI. FIG. 1. and VII. FIG. 2. h´.Return to passage
[981] PLATE VI. FIG. 4, 10. VII. FIG. 1, 2, 4. and XXVI. FIG. 39-41. i.Return to passage
[982] PLATES XI. XII. and XXV.Return to passage
[983] PLATE VI. FIG. 1, 2. and VII. FIG. 1. i´.Return to passage
[984] Ibid. XII. FIG. 6. 9. k´.Return to passage
[985] Ibid. l´´.Return to passage
[986] Ibid. l.Return to passage
[987] Ibid. FIG. 6. m´.Return to passage
[988] Ibid. FIG. 6, 8-10. m´´.Return to passage
[989] PLATE VI. FIG. 2, 8. ê.Return to passage
[990] PLATE VII. FIG. 2. l. Mon. Ap. Angl. i. t. xiii. f. 1. a, e.Return to passage
[991] PLATE VI. FIG. 2. m.Return to passage
[992] Ibid. î.Return to passage
[993] Ibid. n.Return to passage
[994] PLATE XXVII. FIG. 1, 3, 4. n.Return to passage
[995] PLATE VI. FIG. 2. o.Return to passage
[996] PLATE IX. FIG. 7, 10, 11, &c. and XVI. FIG. 4, 8. B.Return to passage
[997] M. Chabrier, in his admirable Mémoires sur le Vol des Insectes. uses the term Tronc Alifère, which suggested the terms here employed.Return to passage
[998] PLATE IX. FIG. 3, 12, 16, &c.Return to passage
[999] Ibid. FIG. 1, 2, 10, 11, &c.Return to passage
[1000] Ibid. FIG. 2. a´.
[1001] Ibid. IX. FIG. 4.
[1002] Ibid. VIII. FIG. 3, 11.
[1003] PLATE XXIX. FIG. 12. c´.
[1004] PLATE VIII. FIG. 2, 11. d´.
[1005] PLATE XXII. FIG. 7. e´.
[1006] M. Latreille, in his Organisation Extérieure des Insectes (Mem. du Mus. viii. 198.) proposes calling the fore-legs of Hexapods Propedes; but having long ago applied this term to the false legs of caterpillars (see above, VOL. II. p. 288. &c.), we shall not adopt it.
[1007] PLATE XXVII. FIG. 36. a´.
[1008] PLATE XV. FIG. 6-9.
[1009] PLATE XXVII. FIG. 59. a.
[1010] PLATE VIII. FIG. 3, 4, 12-14, 16, 17. IX. FIG. 1, 3, 7, 8, 10-12, 15.
[1011] Ibid. c.
[1012] PLATE IX. FIG. 7, 11, 12, 15, 19. g´. The Collare of Hymenoptera and Diptera has usually been regarded as representing the Prothorax of Coleoptera, Orthoptera, &c. But this difference obtains between them--the latter evidently belongs to the Manitrunk, and its muscles do not appertain at all to the Alitrunk; whereas the Collare as evidently is a part of the latter, its muscles belong to it, and its functions in assisting in flight are important. These reasons, and others we shall state hereafter, induced us long ago to consider this part as not representing the Prothorax; and they seem to have induced M. Chabrier almost to adopt a similar opinion. Sur le Vol des Insectes. Ann. du Mus. 3eme Ann. 414. et 4eme Ann. 54--.
[1013] PLATE XXII. FIG. 8, 11. h´.
[1014] Ibid. FIG. 8. PLATE VIII. FIG. 3, 12, 14, 16. IX. FIG. 1, 7, 8, 10-12, 15, 19, 21. i´.
[1015] PLATE VIII. FIG. 14, 20. IX. FIG. 11, 12. and XXII. FIG. 8. b´´.
[1016] PLATE X. FIG. 1.; and XXVIII. FIG. 1-8, 10.
[1017] PLATE XXVIII. FIG. 3-5. b´´´.
[1018] PLATE X. FIG. 1. c´´´.
[1019] PLATE XXVIII. FIG. 6-8. d´´´.
[1020] PLATE XXIII. FIG. 6. e´´´.
[1021] PLATE XXVIII. FIG. 2. a´´´.
[1022] Ibid. FIG. 19. and PLATE X. FIG. 2.
[1023] The upper organs of flight of many of the homopterous section of the Hemiptera seem altogether membranous, and may almost be included under the term Alæ Superiores.
[1024] PLATE X. FIG. 3.
[1025] Ibid. f´´´.
[1026] PLATE X. FIG. 3. g´´´.
[1027] Ibid. FIG. 5-9, 11-15. and PLATE XXVIII. FIG. 18.
[1028] Ibid. h´´´.
[1029] N.B. In the Plate the Costal Area is red, the Intermediate white, and the Anal yellow. When the Hemelytra are considered as divided into Areas, the Membrana might be denominated the Apical Area.
[1030] PLATE X. FIG. 2, 3, b^..
[1031] Ibid. c^..
[1032] PLATE X. FIG. 2, 3. d^..
[1033] Ibid. FIG. 7-15. e^..
[1034] Ibid. f^..
[1035] Ibid. g^..
[1036] Ibid. h^..
[1037] Chabrier Sur le Vol des Insectes, Ann. du Mus. 3eme ann. 428, 4eme ann. 325--. 3d Cahier 78.
[1038] Linn. Trans. i. t. xiii. f. 2. 3. d.
[1039] PLATE X. FIG. 5-15. i^..
[1040] Ibid. a*.
[1041] Ibid. FIG. 6. k^..
[1042] Ibid. l^..
[1043] Ibid. FIG. 5, 6, 13. b*.
[1044] Ibid. FIG. 5-15. m^..
[1045] Ibid. FIG. 5, 6, 13. c*.
[1046] PLATE X. FIG. 5-15. n^..
[1047] Ibid. o^..
[1048] Ibid. FIG. 14. p^..
[1049] Ibid. FIG. 11. m´´´.
[1050] Ibid. FIG. 14, 15. n´´´.
[1051] PLATE IX. FIG. 5, 11. g´´.
[1052] PLATES VIII. IX. XXVIII. k´.
[1053] Ibid. l´.
[1054] PLATE IX. FIG. 7. m´.
[1055] PLATE VIII. FIG. 4, 13, 17.; and IX. FIG. 3, 8, 12. d.
[1056] Ibid. n´.
[1057] PLATES VIII. IX. o´.
[1058] PLATE VIII. FIG. 4, 8, 13, 17. p´.
[1059] PLATE XXII. FIG. 6. q´.
[1060] PLATE XVI. FIG. 4-6. r´.
[1061] PLATE VIII. FIG. 3, 12.; and IX. FIG. 1, 7, 10, 11, 12, 15. c.
[1062] PLATE XXII. FIG. 9, 11. s´.
[1063] PLATE VIII. FIG. 3, 12, 20. and IX. FIG. 7, 10-12, 15, 20. t´.
[1064] Ibid. u.
[1065] PLATES VIII. IX. XXVIII. v´.
[1066] PLATES VIII. and IX. w´.
[1067] PLATE X. FIG. 4, 10.
[1068] PLATE X. FIG. 4. o´´´.
[1069] Linn. Trans. i. t. xiii. f. 1. b. 3. a.
[1070] Kirby Mon. Ap. Angl. i. t. xiii. f. 19.
[1071] De Geer ii. t. ix. f. 9. d.
[1072] Ibid. vi. t. ii. f. 23. a a.
[1073] PLATE IX. FIG. 19. p´´´.
[1074] Ibid. FIG. 7. and PLATE XXII. FIG. 14. k´´.
[1075] PLATE XXII. FIG. 10, 11. x´.
[1076] Ibid. FIG. 9-11. l´´.
[1077] PLATES VIII. and IX. f.
[1078] Ibid. y´.
[1079] Ibid. z´.
[1080] PLATE XXIX. FIG. 15. m´´.
[1081] PLATES VIII. IX. a†.
[1082] PLATE XXVII. FIG. 50.
[1083] PLATE XXII. FIG. 3. b†.
[1084] PLATE VIII. FIG. 18; and XXII. FIG. 13. c†.
[1085] PLATE XIV. FIG. 5-8.
[1086] PLATE VIII. FIG. 2, 4, 11, 13, &c. o´´.
[1087] Ibid. FIG. 18. q´´´.
[1088] PLATE XIV. FIG. 6-8; and XXVII. FIG. 12. p´´.
[1089] Ibid. q´´.
[1090] PLATE XIV. FIG. 5-8; and XXVII. FIG. 6-8. r´´.
[1091] PLATE XXVII. FIG. 7, 8, 15. r´´´.
[1092] PLATE XIV. FIG. 5-8. s´´.
[1093] PLATE XXVII. FIG. 21. s´´´.
[1094] Ibid. FIG. 9, 10, 16, 17. t´´´.
[1095] Ibid. FIG. 34-36. u´´´.
[1096] PLATE XIV. FIG. 6; and XXVII. FIG. 29-36. v´´´.
[1097] PLATE XIV. FIG. 5-8; and XXVII. FIG. 44, 45, 62, 63. t´´.
[1098] PLATE XXVII. FIG. 25, 26, 41. w´´´.
[1099] PLATE XXVII. FIG. 25, 26. x´´´.
[1100] PLATE XXVI. FIG. 47, 48; and XXVII. FIG. 43. r^..
[1101] Ibid. s^..
[1102] PLATE XXVI. FIG. 47, 48. d*.
[1103] PLATE XXVII. FIG. 37-57. e*.
[1104] Ibid. FIG. 56, 57. f*.
[1105] Ibid. FIG. 56. a ψ.
[1106] Ibid. FIG. 59. y´´´.
[1107] PLATE XV. FIG. 9; and XXVII. FIG. 35, 59-61. t^..
[1108] PLATE VIII. FIG. 5, 6, 9, 15, 18, 19.
[1109] Ibid. FIG. 5, 15. A.
[1110] Ibid. A´.
[1111] Ibid. FIG. 5, 9. B´.
[1112] Ibid. FIG. 5, 9, 15. A´´.
[1113] PLATE VIII. FIG. 6, 9, 15. B.
[1114] The scientific reader must recollect that these terms are employed, not because these parts are thought to be true representatives of the Epigastrium and Hypochondria of vertebrate animals, but merely on account of some analogy between them.
[1115] PLATE VIII. FIG. 6. C´.
[1116] Ibid. D´.
[1117] Ibid. B´´.
[1118] Ibid. FIG. 18, 19. C´´.
[1119] Ibid. FIG. 6, 9, 15. E´.
[1120] PLATE VIII. FIG. 9. D´.
[1121] PLATE IX. FIG. 17, 18. C.
[1122] Ibid. FIG. 13. F´.
[1123] Ibid. G´.
[1124] Ibid. FIG. 17. H´.
[1125] Ibid. FIG. 18. I´.
[1126] PLATE XV. FIG. 12. D.
[1127] PLATE VIII. FIG. 5, 15. K´.
[1128] Ibid. FIG. 6, 15, 18. L´.
[1129] PLATE XV. FIG. 18-22; and XVI. FIG. 1-3.
[1130] PLATE XV. FIG. 18. E´.
[1131] PLATE XV. FIG. 22; and XVI. FIG. 2, 3.
[1132] Ibid. FIG. 20, 21; and XVI. FIG. 1. F´´.
[1133] PLATE XV. FIG. 20. G´´.
[1134] Ibid. FIG. 20, 21; and XVI. FIG. 1. II´´.
[1135] Kirby Mon. Ap. Angl. i. t. xii. Apis **. e. 1. neut. f. 23-25; and t. xiii. f. 27, 28.
[1136] Ibid. t. xiii. f. 30, 31.
[1137] Ibid. a.
[1138] PLATE XV. FIG. 12. L´´.
[1139] PLATE XV. FIG. 14. M´´.
[1140] Ibid. FIG. 17. N´´.
[1141] Ibid. FIG. 15. O´´.
[1142] Ibid. FIG. 13. P´´.
[1143] Ibid. FIG. 23. Q´´.
[1144] De Geer iii. t. xxii. f. 10. a a.
[1145] Ibid. t. xxiv. f. 2. c; and f. 11.
[1146] PLATE XV. FIG. 16. R´´.
[1147] Ibid. S´´.
[1148] Ibid. FIG. 10; and PLATE XXIII. FIG. 16, 17. T^*´´.
[1149] Ibid. FIG. 12. B´´´. 15.
[1150] De Geer ubi supr. t. iii. f. 5, 20, 21. c.