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.

[904] _Ibid._ 162. Compare the _Systême des Anim. sans Vertèbr._ of the same author, p. 12--.

[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.

[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.

[907] See above, p. 52--.

[908] See above, p. 43--.

[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.

[910] See above, p. 28--.

[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?

[912] We employ this term instead of _Instrumenta Cibaria_ F., to avoid circumlocution.

[913] PLATES VI. VII. &c. a´, and XXVI. FIG. 30-33.

[914] Ibid. FIG. 30. _Mon. Ap. Angl._ i. 139. _Melitta_ **. b. _t._ ii. _f._ 4, 5.

[915] PLATES VI. VII. &c. and XXVI. FIG. 23-29. b´.

[916] PLATES VI. and VII. a´´, and XXVI. FIG. 34, 35.

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´´.

[918] Ibid.

[919] PLATE XIII. FIG. 7. c´´.

[920] Marcel de Serres _Comparaison des Organes de la Mastication des Orthoptères._ 7. _Ann. du Mus._ 11.

[921] PLATE VI. FIG. 6. c´, a´´´. and XIII. FIG. 5. a´´´.

[922] PLATE VI. FIG. 12. b´´´. and XIII. FIG. 5. b´´´.

[923] PLATE XXVI. FIG. 16. c´´´.

[924] Ibid. FIG. 20. d´´´.

[925] Cuv. _Anat. Comp._ iii. 322--.

[926] PLATES VI. VII. d´. and XXVI. FIG. 9-15.

[927] Ibid. c´´.

[928] Ibid. f´´.

[929] Ibid. and XXVI. FIG. 13-15.

[930] PLATE VI. FIG. 3. d´´´.

[931] PLATE XXVI. FIG. 11. d´´´.

[932] PLATE VI. FIG. 6, 12. d´´´.

[933] Ibid. FIG. 3, 6, 12. and XXVI. FIG. 9, 10. e´´´.

[934] Ibid. VI. FIG. 3, 12. f´´´.

[935] PLATES VI. VII. h´´. XIII. FIG. 1-4, 8. h´´. and XXVI. FIG. 1-8.

[936] PLATE VI. FIG. 6, 12. e´.

[937] PLATE XXVI. FIG. 26, 29. e´.

[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.

[939] Huber _Fourmis_, 4--.

[940] PLATE VII. FIG. 2, 3. and XXVI. FIG. 28. i´´.

[941] PLATE VII. FIG. 14. f´.

[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.

[943] Vide Savigny _Mém. sur les Anim. sans Vertèbr._ I. i. 12--.

[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.

[945] See his _Mémoires sur les Animaux sans Vertèbres_, I. i.

[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.

[947] PLATE VI. FIG. 7-9.

[948] PLATE VI. FIG. 7, 9. b´.

[949] Ibid. c´.

[950] Ibid. d´.

[951] Ibid. VII. FIG. 5, 6.

[952] Ibid. b´.

[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.

[955] PLATE VII. FIG. 5. a´, c´, d´.

[956] PLATE VII. FIG. 5, 6. a´.

[957] Ibid. c´.

[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.

[959] PLATE VI. FIG. 13.

[960] Ibid. _a._

[961] Ibid. _b._

[962] Ibid. Labrum a´; Mandibulæ c´; Maxillary Palpus h´´.

[963] PLATE VII. FIG. 8.

[964] Ibid. c´.

[965] Ibid. d´. Maxillary Palpi h´´.

[966] Ibid. e´.

[967] PLATE VII. FIG. 11, 13. _f_´.

[968] Ibid. FIG. 11. _d_´.

[969] See above, p. 18, &c.

[970] PLATE VI. FIG. 10. c´.

[971] PLATE VI. FIG. 1, 4, 10. â.

[972] Ibid. a.

[973] Ibid. g´.

[974] PLATE VI. c.

[975] Ibid. d.

[976] Ibid. e.

[977] Ibid. f.

[978] Ibid. g.

[979] PLATES VI. VII. and XXVI. h.

[980] PLATE VI. FIG. 1. and VII. FIG. 2. h´.

[981] PLATE VI. FIG. 4, 10. VII. FIG. 1, 2, 4. and XXVI. FIG. 39-41. i.

[982] PLATES XI. XII. and XXV.

[983] PLATE VI. FIG. 1, 2. and VII. FIG. 1. i´.

[984] Ibid. XII. FIG. 6. 9. k´.

[985] Ibid. l´´.

[986] Ibid. l.

[987] Ibid. FIG. 6. m´.

[988] Ibid. FIG. 6, 8-10. m´´.

[989] PLATE VI. FIG. 2, 8. ê.

[990] PLATE VII. FIG. 2. l. _Mon. Ap. Angl._ i. _t._ xiii. _f._ 1. _a_, _e_.

[991] PLATE VI. FIG. 2. m.

[992] Ibid. î.

[993] Ibid. n.

[994] PLATE XXVII. FIG. 1, 3, 4. n.

[995] PLATE VI. FIG. 2. o.

[996] PLATE IX. FIG. 7, 10, 11, &c. and XVI. FIG. 4, 8. B.

[997] M. Chabrier, in his admirable _Mémoires sur le Vol des Insectes_. uses the term _Tronc Alifère_, which suggested the terms here employed.

[998] PLATE IX. FIG. 3, 12, 16, &c.

[999] Ibid. FIG. 1, 2, 10, 11, &c.

[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._