[814] Ibid. _t._ xxiii. _f._ 35.
[815] Ibid. _t._ ii. _f._ 7.
[816] Ibid. _t._ v. _f._ 40.
[817] Ibid. xix. _f._ 175.
[818] Ibid. _t._ xii. _f._ 115.
[819] _Copris floriger_ Kirby in _Linn. Trans._ xii. 396.
[820] Oliv. no. 3. _t._ ii. _f._ 18.
[821] Ibid. _t._ xxii. _f._ 32.
[822] Ibid. _t._ ix. _f._ 85.
[823] Ibid. _t._ iii. _f._ 22.
[824] Ibid. _t._ xiii. _f._ 124. _a._
[825] Ibid. _t._ v. _f._ 38.
[826] Ibid. _t._ xxviii. _f._ 242. _t._ xviii. _f._ 169.
[827] Ibid. _t._ xvi. _f._ 152.
[828] Ibid. _t._ xxviii. _f._ 247.
[829] Ibid. _t._ xv. _f._ 138. _a. t._ v. _f._ 33.
[830] Samouelle's _Compend._ _t._ i. _f._ 1.
[831] Oliv. no. 3. _t._ v. _f._ 36. _a._
[832] _Schon. Synon._ i. _t._ 1.
[833] Oliv. no. 3. _t._ xxiv. _f._ 208.
[834] Ibid _t._ x. _f._ 88.
[835] Ibid. _f._ 87.
[836] Ibid. _t._ xx. _f._ 185.
[837] Ibid. _t._ vi. _f._ 42. _a._
[838] Ibid. n. 83. _Curculio_ _t._ xxii. _f._ 295.
[839] Oliv. no. 81. _Attelabus_ _t._ ii. _f._ 27. _b._ 28.
[840] De Geer ii. _t._ xxxi. _f._ 18-22.
[841] Ibid. iii. 21.
[842] Lesser L. i. 185.
[843] De Geer iii. 308.
[844] See above, VOL. II. 394--.
[845] _Linn. Trans._ i. 145. 135--.
[846] _Ibid._ _t._ xiii. _f._ 1. 2. ♂. 3. ♀.
[847] _Mon. Ap. Angl._ i. _t._ xi. Apis **, a. 2. α. β. _f._ 18.
[848] Oliv. no. 68. _Saperda_ _t._ i. _f._ 8.
[849] _Mon. Ap. Angl._ i. _t._ viii. _f._ 28. _c._
[850] _Ibid._ _t._ ix. Apis **. c. 2. β. _f._ 12.
[851] Clairv. _Ent. Helv._ ii. _t._ xii. _f._ B.
[852] Oliv. _Ins._ no. 66. _t._ iii. iv. _f._ 12.
[853] Ibid. no. 3. _t._ iv. _f._ 27.
[854] _Punaises_, _t._ iii. _f._ 20.
[855] Mr. Marsham has made two species of this from this
circumstance, viz. _Necydalis Podagrariæ_ and _simplex_.
[856] Oliv. n. 3. _t._ xxvii. _f._ 27. ♀. and _t._ iv. _f._ 27. ♂.
[857] Ibid. _t._ vii. _f._ 58. ♂. _f._ 57. ♀.
[858] Ibid. n. 95. _Hispa_ _t._ i. _f._ 4. PLATE XXVII. FIG. 24.
[859] PLATE XV. FIG. 3.
[860] De Geer i. _t._ vii. _f._ 14, 15.
[861] Coquebert _Illust. Icon._ i. _t._ vi. _f._ 6. PLATE XXVII. FIG.
32.
[862] Illig. _Mag._ iv. 214. Gyllenhal. _Insect. Suec._ i. 168.
[863] PLATE XV. FIG. 9.
[864] Ibid. FIG. 8.
[865] Christ. _Hymenopt._ 118. _t._ iv. _f._ 3.
[866] _Mon. Ap. Angl._ i. _t._ xi. _Apis_ **. e. 1. ♂. _f._ 8. _e._
and _t._ xii. **. e. 1. neut. _f._ 19. _c._
[867] _Hor. Entomolog._ 144.
[868] PLATE XXVII. FIG. 45. _a._
[869] De Geer ii. _t._ xxviii. _f._ 2.
[870] _Mon. Ap. Angl._ i. _t._ v. _Apis_ **. a. _f._ 10. ♂. 11. ♀.
[871] _Ibid._ _t._ vii. Apis **. c. 1. α. 17. ♀. 18. ♂.
[872] _Ibid._ _t._ viii. _f._ 30. ♂. 31. ♀.
[873] _Ibid._ _t._ xi. Apis **. e. 1. mas. _f._ 9. _t._ xii. Apis **.
e. 1. fem. _f._ 9. and neut. _f._ 22.
[874] De Geer vi. _t._ xviii. _f._ 12, 13.
[875] De Geer v. 151--.
[876] _Mon. Ap. Angl._ i. 177. _t._ ix. Apis **. c. 2. γ. _f._ 11.
_a_, _d_.
[877] _Ibid._ _f._ 13. _a._
[878] See above, VOL. II. 395.
[879] PLATE XXIX. FIG. 13. Stoll. _Spectres_, &c. _t._ xxv. _f._ 99.
[880] Sparrman. _Voyage_, i. 312--.
[881] _Coleopt. Micropt._ 16.
[882] _Mon. Ap. Angl._ i. _t._ viii. _f._ 25. De Geer iii. 255. _t._
xiv. _f._ 8.
[883] _Mon. Ap. Angl._ i. _t._ viii. _f._ 24.
[884] _Ibid._ _t._ ix. Apis xx. c. 2. γ. _f._ 12.
[885] _Ibid._ Apis **. c. 2. β. _f._ 11.
[886] _Ibid._ _t._ vii. Apis **. c. 1. α. _f._ 11, 12. ♀. 13, 14. ♂.
[887] PLATE XV. FIG. 12. De Geer ii. _t._ xxiv. _f._ 9, 10. ♀. _t._
xxv. _f._ 2, 3. ♂.
[888] Reaum. vi. 494. _t._ xliv. _f._ 3-11.
[889] De Geer ii. _t._ xvii. _f._ 5-7.
[890] _N. Dict. d'Hist. Nat._ xxxii. 443.
[891] See above, VOL. II. 110, 118.
[892] VOL. I. 283.
[893] II. i. 6.
[894] Clairville _Ent. Helvet._ ii. 214--. I have seen it asserted in
some popular work on _Natural History_, (the title of which I do not
recollect,) that _Mantis religiosa_ has been known to live ten years;
and a _flea_, when fed and taken care of, six. But this is so contrary
to experience in other cases, that the statement seems quite incredible.
[895] Rösel III. 379. _N. Dict. d'Hist. Nat._ ii. 285.
[896] Dumeril _Traité Elément._ ii. 87. n. 683.
[897] De Geer ii. 288.
[898] Huber i. 106.
[899] _N. Dict. d'Hist. Nat._ ix. 553.
[900] VOL. II. 173--.
[901] Morier's _Second Journey through Persia_, 100.
[902] VOL. II. 175.
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_.
INSERT FOLDOUT HERE
INSERT FOLDOUT HERE
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_.