The tail of some species of the genus Ephemera is furnished with three long, jointed, hairy bristles. We learn from Reaumur with respect to one, that though in the female these are all equal in length, yet in the male there is only a rudiment of the third. On the belly near the anus these males have four fleshy appendages, the posterior ones setaceous and long, and the anterior pair filiform and shorter. They are supposed to represent the anal forceps of other insects[888]. In Ephemera vulgata, described by De Geer, both sexes have three bristles, but those of the male are the longest; and he describes the forceps as consisting of only a pair of jointed pieces, forming a bow not unlike the forceps of an earwig[889].
v. All the differences I have hitherto noticed between the sexes of insects occur in their bodily structure; but there are others of a somewhat higher description observable in their character. You may smile at the idea of character in beings so minute; but if you recollect what I formerly related to you when treating upon the societies of insects, you will allow that something of this kind does take place amongst them. In general the males are more fitted for locomotion and more locomotive; and the females, on the contrary, are necessarily more stationary. And this for an obvious reason:—the law is, that the male shall seek the female, and therefore he is peculiarly gifted for this purpose, both in his organs of sensation and motion: while his partner in many cases has very simple antennæ, he has very complex ones; and while she has either no wings or only rudiments of them, he is amply provided with them. Again: amongst the insects that suck the blood of man or beast, such as the gnat (Culex) or horse-flies (Tabanidæ), it is the female alone that is bloodthirsty, the males contenting themselves with the nectar of flowers[890]. But the difference of character in the sexes is most conspicuous, at least it has been more noticed, in those that live in societies, and is quite the reverse of what takes place in the human species. While the females and workers (which are now generally considered as sterile females, in which the ovaries are not developed) are laborious and active, diligent and skilful, wise and prudent, courageous and warlike;—the males, on the contrary, take no part in promoting the common weal, except merely a sexual one. Though till a certain period they are supported at the expense of the community, they take no part in its labours, either in collecting and forming the public stores, or in feeding and attending the young. They are idle, cowardly, and inactive; have neither art nor skill of any kind, and are unprovided with the usual offensive weapons of their species. These observations in their full force apply particularly to the hive-bee, and partially to the other social insects; amongst which, if you consult my former communications, there are some exceptions to this slothful character in the males[891].
II. Age. There is less diversity in the duration of the lives of insects in their perfect than in their larva or pupa state. Some, like several species of Ephemeræ, live only a few hours; some never even see the sun[892]: others, as flies, moths, and butterflies, and indeed the majority of insects, a few days or weeks; and a comparatively small number, such as some of the larger Coleoptera, Orthoptera, &c., six, nine, twelve, or fifteen months—a period beyond which the life of perfect insects rarely extends. Some, however, certainly enjoy a longer existence in the perfect state. Mr. Baker kept one of the darkling beetles (Blaps Mortisaga) alive under a glass upwards of three years. The rose-beetle (Cetonia aurata), Rösel informs us he fed with fruit and moist white bread for as long a period[893]. Esper kept our most common water-beetle (Dytiscus marginalis) in water in a large glass vessel, feeding it with meat, for three years and a half[894]. With regard to the Arachnida, from the very slow growth of Scorpio europæus, Rösel suspects that it must live two or three years; and Audebert is stated to have kept a spider for several[895]. In this respect insects follow a law very different from that which obtains amongst vertebrate animals. In these the duration of their life is in proportion to the term of their growth: those which attain to maturity the latest, in almost every case living the longest. In insects, on the contrary, we often meet with the very reverse of this rule. Thus the larva of the great goat-moth (Cossus ligniperda) is three years, that of the cabbage-butterfly (Pieris Brassicæ) not three months, in attaining maturity; yet the perfect insects live equally long. Melolontha vulgaris, which in its first state lives four years, as a beetle lives only eight or ten days[896]. And some Ephemeræ, whose larvæ have been two years in acquiring their full size, live only an hour; while the flesh-fly, whose larva has attained to maturity in three or four days, will exist several weeks.
There is yet another anomaly in the duration of the life of perfect insects. This is not, as in larger animals, a fixed period liable to be shortened only by accident or disease, and incapable of being prolonged; but an indeterminate one, whose duration is dependent on the earlier or later fulfilment of a particular animal function—that of propagation. The general law is, that a few days, or at most weeks, after the union of the sexes, both perish, the female having first deposited her eggs. If, therefore, this union takes place immediately after the disclosure of the insect from the pupa, their existence in the perfect state will not exceed a few days or weeks, or in some cases hours, as in that of the Ephemera, and likewise of the Phalænæ Attaci L. &c., which fall down dead immediately after oviposition[897]. But if by any means it be put off or prevented, their life may be protracted to three or four times that period. Gleditsch asserts, that by keeping apart the sexes of a grasshopper, their lives were prolonged to eight or nine weeks, instead of two or three, their ordinary length; and under similar circumstances Ephemeræ, which usually perish in a day, have been kept alive seven or eight. It is in consequence of this very curious fact, which has not received from physiologists the attention that it merits, that many butterflies and other insects, which, when excluded from the pupa in summer, perish in less than a month, live through the winter, if excluded late in the autumn, and the union of the sexes does not ensue. It is probable that the great age to which Baker's Blaps, Rösel's Cetonia, and Esper's Dytiscus attained, was owing to their being virgins when taken, and subsequently kept from any sexual intercourse. A parallel case happens in the vegetable kingdom:—if annual plants are kept from seeding, they will become biennial; as, likewise, if they are sown too late in the year to produce seeds.
In the case, however, of the earlier or later exclusion of the imago, another agent has probably some influence. Buffon found that, other circumstances being alike, the silkworm-moths placed in a northern, lived longer than those exposed to a southern aspect: whence it appears that the stimulus of heat shortens the lives of insects, and consequently that cold tends to lengthen them.
It must be observed too, that as the death of the female insect does not take place until all the eggs are excluded, the term of her life, though usually short in the majority of species, which lay their whole number at once, is proportionably long in those which, like the queen-bee, have a longer period assigned them for this important office. Huber affirms, that he had certain proofs that she was engaged for two years in laying eggs, all impregnated by a single sexual union[898]; and in the females of most insects that live in society, several months are required to mature the last eggs that are in the ovary. There is one tribe of insects, however, the females of which are affirmed to survive this operation: I mean Dorthesia Bosc; after which they even moult, though not so often as before[899].
I formerly related to you the singular fact, that the drones in a beehive at a certain period are without mercy slaughtered by the workers[900]. A fact the reverse of this is recorded by Morier with respect to the locusts: he affirms that the female, when she has done laying her eggs, is surrounded and killed by the males. He says that he never himself witnessed this extraordinary circumstance; but that he heard it from such authority that he gave full credit to it[901]. It is a fact, however, that seems to require further evidence to entitle it to such credit. These are instances in which, by a law of nature, the life of these insects is shortened by violence. It does not appear to have been ascertained how long those drones live that, under particular circumstances, as stated in a former letter[902], are exempted from the usual slaughter.
I am, &c.
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].