Chapter III: Letter XXVIII: Definition of the Term Insect (2)

It is worthy of remark here, that although the tropical species of a genus usually exceed those of colder climates in size, the _Gryllotalpa_ of Brazil is very considerably smaller than that of Europe: whether this is the case with the rest of the cricket tribe I have not had an opportunity of ascertaining. The _Lepidoptera_, though often remarkable for the vast expansion of their "sail-broad vans," if you consider only their bodies, never attain to gigantic bulk. Even the hawk-moths (_Sphinx_ L.), though usually very robust, make no approach to the size of the great beetles, or the length of some of the spectres (_Phasma_) and dragon-flies (_Agrionidæ_). With regard to the superficial contents of their wings, a considerable difference obtains in different species where they expand to the same length--for the _secondary_ wings are sometimes smaller than the _primary_, and sometimes they equal them in size. In some instances, also, the latter although long are narrow, and in others they are nearly as wide as long: regard, therefore, should be had to their expansion both ways. In the _Hymenoptera_ and _Diptera_, the principal giants are to be found in the predaceous or blood-sucking tribes, as _Scolia_, the _Sphecidæ_, _Pompilidæ_, _Vespidæ_, &c., belonging to the former order; and the _Asilidæ_ and _Tabanidæ_ to the latter. The true and false humble bees (_Bombus_ and _Xylocopa_) and the fly tribe (_Muscidæ_), though they sometimes attain to considerable size, scarcely afford an exception to this observation. Amongst the _Aptera_ none of the _Hexapods_ strike us by their magnitude, and few of the _Octopods_, though the legs of some of the _Phalangidæ_ inclose a vast area. That in the table would with them describe a circle of six inches diameter, though its body is little more than a quarter of an inch in length. The _Myriapods_ exceed most insects in the vast elongation of their body, which with their motion gives them no slight resemblance to the serpents. In the class _Arachnida_, the bird-spiders (_Mygale_) are amongst the principal giants, nor do the _Scorpions_ fall far short of them--both of them when alive often alarming the beholder as much by their size as by their aspect.

But as I have before observed, generally speaking, one of the most remarkable characters of the insect world, is the little space they occupy; for though they touch the vertebrate animals and even quadrupeds by their giants, yet more commonly in this feature they go the contrary way, and by their smallest species reach the confines of those microscopic tribes that are at the bottom of the scale of animal life. I possess an undescribed beetle, allied to _Silpha minutissima_ E. B.[50], which, though furnished with elytra, wings, antennæ, legs, and every other organ usually found in the order it belongs to, is absolutely not bigger than the full stop that closes this period. In several other coleopterous genera there are also very minute species, as in _Cryptophagus_, _Anisotoma_, _Agathidium_, &c. I know no _orthopterous_ insect that can be called extremely minute, except that remarkable one found on the Continent in the nests of ants, the _Blatta Acervorum_ of Panzer[51], but now called, I believe, _Myrmecophilus_: nor indeed any in the _Hemiptera_, _Neuroptera_, and _Diptera_, that approach the extreme limits of visibility: but in the _Lepidoptera_, the pygmy _Tinea occultella_ is almost invisible except in flight, being scarcely thicker than a horse's hair, and proportionably short; indeed, many others of those lovely Lilliputians, the subcutaneous _Tineæ_, decorated with bands of gold and silver, and studded with gems and pearls, that in larger species would dazzle the beholder's eye, are in size not much more conspicuous. In the _Hymenoptera_ order, _Ichneumon Punctum_ of Dr. Shaw, which forms so striking a contrast to his giant _Phasma dilatatum_, being placed together in the same plate; and another that I possess, under the trivial name of _Atomos_, would elude the searching eye of the entomologist unless when moving upon glass. Linné named the tribe of parasites to which these belong, _Minuti_, on account of their generally diminutive size. But these little minims, under the superintendence of Providence, are amongst the greatest benefactors of the human race, since they keep within due bounds the various destroyers of our produce.

The number of minute species of insects seems greatly to exceed that of large ones, at least in Europe, of which it may be asserted probably with truth, that two-thirds are under a quarter of an inch in length, and one-third not exceeding much a duodecimal of it. It might hold good perhaps in _Coleoptera_, _Hymenoptera_, _Diptera_, and _Aptera_: but in _Orthoptera_, _Hemiptera_, _Neuroptera_, and especially _Lepidoptera_, a large proportion would be found to exceed three lines in length. Neither can it be affirmed of extra-European species, of those at least preserved in cabinets, amongst which it is rare to find an insect less than the fourth of an inch long. This, however, must probably be attributed to the inattention of collectors, who neglect the more minute species.

* * * * *

Though size forms a pretty accurate distinction between insects and the great bulk of _vertebrate_ animals, it affords less assistance in separating them from the _invertebrate_ classes, which are of every size, from the monstrous bulk of some _Cephalopoda_ (cuttle-fish) and _Mollusca_ (shell-fish, &c.) to the invisible infusory animalcule: but external characters, abundantly sufficient for this purpose, may be drawn from the general covering, substance, form, parts, and organs of the body. As I shall enter into pretty full details upon this subject when I come to treat of the external anatomy of insects, I shall here, therefore, only give such a slight and general sketch of the distinctions just mentioned, as will answer the end I have in view. I must here repeat what I have before observed, and what it is necessary that you should always bear in mind, namely, that at the limits of classes and of every other natural group, the characters begin to change, those peculiar to the one group beginning gradually to disappear, and those of the other to show themselves; so that it is impossible almost to draw up a set of characters so precise as exactly in every respect to suit all the members of any natural group.

Whichever way we turn our eyes on the objects of creation, above--below--athwart, _analogies_ meet us in every direction, and it appears clear, that the Book of Nature is a Book of Symbols, in which one thing represents another in endless alternation. And not only does one animal, &c. symbolize another, but even between the parts and organs of one set of animals there is often an _analogy_ as to their _situation_ and _use_, when there is little or no _affinity_ as to their _structure_--or again, the analogy is in their _situation_, without affinity in either structure or use. Thus certain parts in one tribe represent other certain parts of another tribe, though as to their structure there is often a striking disagreement. This is particularly observable between the vertebrate and invertebrate animals. I shall therefore, in my remarks on the general and particular structure of insects, contrast it in its most important points with that of the first-mentioned tribe.

The first thing that strikes us when we look at an insect is its outside _covering_, or the case that incloses its muscles and internal organs. If we examine it attentively, we find that it is not like the skin of quadrupeds and other _Vertebrata_, covering the whole external surface of the body; but that in the large majority it consists of several pieces or joints, in this respect resembling the skeleton of the animals just named; and that even in those in which the body appears to have no such segments, as in many of the Mites (_Acarus_ L.), they are to be found in the _limbs_. This last circumstance, to have externally jointed legs, is the peculiar and most general distinction by which the _Insecta_ of Linné, including the _Crustacea_, may always be known from the other invertebrate animals[52].

If we proceed further to examine the _substance_ of this crust or covering, though varying in hardness, we shall find it in most cases, if we exclude from our consideration the shells of the _Mollusca_, &c., better calculated to resist pressure than that of the majority of animals that have no spine. In all the invertebrate tribes, indeed, the muscles, there being no internal skeleton, are attached to this skin or its processes, which of course is firmer than the internal substance; but in insects it is very often rigid and horny, and partially difficult to perforate, seldom exhibiting that softness and flexibility which is found in the cuticle of birds and most quadrupeds. From this conformation it has been sometimes said, that insects carry their _bones_ on the _outside_ of their body, or have an _external_ skeleton. This idea, though not correct in all respects, is strictly so in this--that it affords a general point of support to the muscles, and the whole structure is erected upon it, or rather I should say within it. The difference here between _Insects_ and the _Vertebrata_ seems very wide; but some of the latter make an approach towards it. I allude to the Chelonian Reptiles (_Testudo_ L.), in which the vertebral column becomes external or merges in the upper shell. The _cyclostomous_ fishes also are not very wide of insects as to their integument. But on this subject I shall be more full hereafter.

The _forms_ of insects are so infinitely diversified that they almost distance our powers of conception: in this respect they seem to exceed the fishes and other inhabitants of the ocean, so that endless diversity may be regarded as one of their distinctions. But on all their variations of form the Creator has set his seal of symmetry; so that, if we meet with an animal in the lower orders in which the parts are not symmetrical, we may conclude in general that it is no insect.

But it is by their _parts_ and _organs_ that insects may be most readily distinguished. In the _vertebrate_ animals, the body is usually considered as divided into _head_, _trunk_, and _limbs_, the _abdomen_ forming no part of the skeleton; but in the _insect_ tribes, besides the organs of sense and motion, the body consists of _three_ principal parts--_Head_, _Trunk_, and _Abdomen_--the _first_, as was before observed, bearing the principal organs of _sense_ and _manducation_; the _second_ most commonly those of _motion_; and the third those of _generation_--the organs of respiration being usually common to both trunk and abdomen. These three primary parts,--though in some insects the head is not separated from the trunk by any suture, as for instance in the _Arachnida_; and in others, head, trunk, and abdomen form only _one_ piece, as in some mites,--still exist in all, and in the great majority they are separated by incisures more or less deeply marked: this is particularly visible in the _Hymenoptera_ and _Diptera_, which, in this respect, are formed upon a common model; and in the rest, with the above exceptions, it may be distinctly traced.

The _head_ of insects is clearly analogous to that of vertebrate animals, except in one respect, that they do not breathe by it. It is the seat probably of the same senses as _seeing_, _hearing_, _smelling_, _tasting_--and more peculiarly perhaps of that of _touch_. The _eyes_ of insects, though allowed on all hands to be organs of _sight_, are differently circumstanced in many particulars from those of the animals last mentioned; they are fixed, have neither iris nor pupil, are often compound, and are without eyelids to cover them during sleep or repose; there are usually two compound ones composed of hexagonal facets, but in some instances there are four; and from one to three simple in particular orders. The _antennæ_ of insects in some respects correspond with the _ears_ of the animals we are comparing with them; but whether they convey the vibrations of sound has not been ascertained: that they receive pulses of some kind from the atmosphere I shall prove to you hereafter--so that if insects do not _hear_ with them in one sense, they may, by communicating information, and by _aëroscopy_, to use Lehman's term, not directly in his sense[53], supply the place of ears, which would render them properly analogous to those organs. That in numbers these remarkable organs are _tactors_ is generally agreed, but this is not their _universal_ use. That insects _smell_ has been often proved; but the organ of this sense has not been ascertained. What has improperly been called the _clypeus_, or the part terminating the face above the upper lip (_labrum_), is in the situation of the _nose_ of the _Vertebrata_, and therefore so far analogous to it, and in some cases even in form: I therefore call it the _nose_. Whether this part represents the nose by being furnished with what answer the purpose of _nostrils_, residing somewhere at or above the suture that joins it to the upper lip, I cannot positively affirm; but from the observations of M. P. Huber, with regard to the hive-bee, it appears that at least these insects have the organ of the sense in question somewhere in the vicinity of the mouth, and above the tongue[54]: analogy, therefore, would lead us to look for its site somewhere between the apex of the nose and the upper lip; and in some other cases, which I shall hereafter advert to, there is further reason for thinking that it actually resides at the apex of the nose. The organ of _taste_ in insects, though some have advanced their _palpi_ to that honour, is doubtless in some part within the mouth analogous in a degree to the tongue and palate of the higher animals. The organs of manducation, in what may be deemed the most perfect description of mouth, consist of an _upper lip_ closing the mouth above, a pair of _mandibles_ moving horizontally that close its upper sides, and a _lower lip_ with a pair of _maxillæ_ attached to it, which close the mouth below and on the under sides, both labium and maxillæ being furnished with jointed moveable organs peculiar to annulose pedate animals, called palpi. In some tribes these organs assume a different form, that they may serve for suction; but though in many cases some receive an increment at the expense of others, and a variation in form takes place, none, as M. Savigny has elaborately proved, are totally obliterated or without some representative[55]. The organs now described, except the upper lip, are formed after a quite different type from those of _Vertebrata_, with which they agree only in their oral situation and use.

The second portion of the body is the _Trunk_, which is interposed between the head and abdomen, and in most insects consists of three principal segments, subdivided into several pieces, which I shall afterwards explain to you. I shall only observe, that some slight analogy may perhaps be traced between these pieces and the vertebræ and ribs of vertebrate animals, particularly the Chelonian reptiles. This is most observable in _Gryllus_ L. and _Libellula_ L., in which the lateral pieces of the trunk are parallel to each other[56]. In the _Diptera_ and many of the _Aptera_ most of these pieces are not separated by sutures. Each of the segments into which the trunk is resolvable bears a pair of jointed _legs_, the first pair pointing to the _head_, and the two last to the _anus_. These legs in their composition bear a considerable analogy to those of quadrupeds, &c., consisting of _hip_, _thigh_, _leg_, and _foot_; but the last of these, the foot or _Tarsus_, is almost universally monodactyle, unless we regard the _Calcaria_ that arm the end of the tibia, as representing fingers or toes, an idea which their use seems to justify. _Acheta monstrosa_ and _Tridactylus paradoxus_, however[57], exhibit some appearance of a phalanx of these organs. They differ from them first in number, the thoracic legs being invariably _six_ in all insects, with the exception of the _Octopods_ or most of the _Trachean Arachnida_, which have usually _eight_. In the _Myriapods_, though there are hundreds of _abdominal_ legs, only six are affixed to the _trunk_. Next they differ with regard to the _situation_ of their legs; for though the anterior pair or arms are analogous in that respect, the posterior pair are not, since in _quadrupeds_ these legs are placed _behind_ the abdomen, but in _insects before_ it--in fact, in the former the legs may be considered as placed at each end of the body, excluding only the head and tail, but in the latter in the middle. Though they correspond with those of quadrupeds in being in _pairs_ or opposite to each other, yet their direction with respect to the body is different, the legs of quadrupeds, &c. being nearly straight, whereas in insects they are bent or form an angle, often very obtuse at the principal articulations, which occasions them to extend far beyond the body, and when long to inclose a proportionally greater space. The _wings_ are the organs of motion with which the upper side of the trunk is furnished; and these, though they are the instruments of flight, are in no other respect analogous to those of birds, which replace the anterior legs of quadrupeds, but approach nearer, both in substance and situation, to the fins of some fishes, and perhaps in some respects even to the leaves of plants. M. Latreille is of opinion, That the four wings or their representatives replace the four thoracic legs of the decapod _Crustacea_[58]. Upon this opinion, which shows great depth of research and practical acumen, I shall have occasion to express my sentiments when I come to treat more at large on the anatomy of the trunk and its members; at any rate they do not replace the two anterior pair of legs of the hexapod _Aptera_. When merely used as wings, they commonly consist of a fine transparent double membrane, strengthened by various longitudinal and transverse nervures, or bones as some regard them, accompanied by air-vessels, of which more hereafter, as well as of their kind and characters. I shall only observe, that insects are known from all other winged animals, by having _four_ wings, or what represent them, and this even generally in those that are supposed to have only a pair. Another peculiarity distinguishes the trunk of insects that you will in vain look for in the vertebrate animals--these are one or two pair of lateral _spiracles_ or breathing pores. Though the respiratory sacs, &c. of birds are almost as widely dispersed as the tracheæ and bronchiæ of insects[59], yet their respiration is perfectly pulmonary, and nothing like these pores is to be discovered in them.

The principal peculiarity of the third part of the body, the _abdomen_, is its situation behind the posterior pair of thoracic legs, and its rank as forming a distinct portion of what represents the skeleton. In most insects it is so closely affixed to the posterior part of the trunk as to appear like a continuation of it, but in the majority of the _Hymenoptera_ and _Diptera_, and in the _Araneidan Arachnida_, or spiders, it is separated by a deep incisure; and in the first-mentioned tribe is mostly suspended to the trunk by a footstalk, sometimes of wonderful length and tenuity. In the _Mammalia_ the _male_ genital organs are partly external; but in insects as well as in many of the vertebrate animals, except when employed, they are retracted within the body. This part is the principal seat of the respiratory pores or spiracles, many having eight in each side, while others have only one.

* * * * *

Such are the principal external characters which distinguish _Insecta_ and _Arachnida_, or what we have heretofore regarded as insects, to which here may be added another connected with their internal organization. The union of the sexes takes place in the same manner as amongst larger animals; and the females with very few exceptions, more apparent than real, are oviparous. They are, however, distinguished by this remarkable peculiarity already alluded to, that, except in the case of the _Arachnida_, one impregnation fertilizes all the eggs they are destined to produce. In most cases, after these are laid, the females die immediately, and the males after they have performed their office, though they will sometimes unite themselves to more than one female. One other circumstance may be named here--that no genuine insect or Arachnidan has yet been found to inhabit the ocean.

Before I conclude this letter, it is necessary to apprize you, that every thing which it contains relative to the characters of insects, has reference to them only in their _last_ or perfect state, not in those preparatory ones through which you are aware that the majority of them must pass. The peculiar characteristics of them in these states--in the _egg_, the _larva_, and the _pupa_, will be the subjects of my next letters, which will be devoted to a more detailed view of the metamorphosis of insects than I gave you before when adverting to this subject[60].

FOOTNOTES:

[1] Εναιμα, Αναιμα. _Hist. Animal._ l. i. c. 6.

[2] _Hist. Animal._ l. i. c. 5, 6: compare 1. v. c. 3 and 33, and _De Partibus Animal._ l. iv. c. 1 and 11.

[3] Το δε σκληρον αυτων ου σθραυσον αλλα φλασον.

[4] _Hist. Animal._ l. iv. c. 1.

[5] Εντομα πολυποδα μεν γαρεσι παντα. _De Part. Animal._ l. iv. c. 6.

[6] _Hist. Animal._ l. iv. c. 19.

[7] The insection that distinguishes these parts, the abdomen especially, is most visible in the majority of the _Hymenoptera_ and _Diptera_ orders; next in some _Coleoptera_, as the _Lamellicorn_ tribes, &c. and the _Lepidoptera_. Latreille is of opinion, that the two last segments of the thorax in some insects are represented by the first of the abdomen, and that the upper half segment of this part in _Coleoptera_ also represents the same. Latr. _De quelques Appendices, &c._ _Annales Générales des Sciences Physiques._ A Bruxelles, vi. livrais, xviii. 14. In fact, in the _Lepidoptera_, when the abdomen is separated from the trunk, this segment usually remains attached to the latter. In the _Myriapods_, the trunk is to be distinguished from the abdomen only by its bearing the three first pair of legs.

[8] There is no general rule without exceptions, and no character is so universal as to be distinctly exhibited by every member of a class or other natural group. Thus, in the majority of the _mites_ (_Acarus_ L.) the body is marked by no segments, and the only articulation or incision is in the legs, palpi, &c. But as the exception does not make void the rule, so neither does the extenuation or absence of some primary character at its points of junction with others, in some individuals, annihilate the class or group.

[9] _Hist. Nat._ l. xi. c. 1.

[10] Animalcula polypoda, _spiraculis_ lateralibus respirantia, cute ossea cataphracta; _antennis_ mobilibus sensoriis instruuntur. _Syst. Nat._ ed. 12. i. 533.

[11] Quoted by Mr. Wm. MacLeay in his very remarkable and learned work _Horæ Entomologicæ_, in which he inclines to the same opinion. 383.

[12] Treviranus (_Ueber den innern Bau der Arachniden_, &c. 22.) always calls the palpi of spiders "_Fülhörner_." In _Scorpio_ he regards them as palpi (_Palpen_).

[13] _N. Dict. d'Hist. Nat._ xvi. 181.

[14] Treviranus, _ut supra_, 48. For the nervous system of scorpions, see _t._ i. _f._ 13; and for that of spiders, _t._ v. _f._ 45.

[15] PLATE XXIX. FIG. 2. Treviranus, _t._ i. _f._ 1.

[16] Cuvier _Anat. Comp._ iv. 407.

[17] _N. Dict. d'Hist. Nat._ ix. 190.

[18] The females of _Dorthesia_, however, a genus related to _Coccus_, are said to survive laying their eggs. _N. Dict. d'Hist. Nat._ ix. 553.

[19] _Anim. sans Vertebr._ i. 381.

[20] _Anim. sans Vertebr._ i. 457.

[21] The number _five_, which Mr. MacLeay assumes for one basis of his system as consecrated in _Nature_, seems to me to yield to the number _seven_, which is consecrated both in _Nature_ and _Scripture_. Metaphysicians reckon _seven_ principal operations of the mind; musicians _seven_ principal musical tones; and opticians _seven_ primary colours. In Scripture the abstract idea of this number is--_completion_--_fullness_--_perfection_. I have a notion, but not yet sufficiently matured, that Mr. MacLeay's _quinaries_ are resolvable into _septenaries_.

[22] _Anim. sans Vertebr._ i. 381.

[23] See on this point MacLeay, _Hor. Entomolog._ 209--.

[24] _Anim. sans Vertebr._ iii. 243.

[25] _Ibid._ iii. 245.

[26] _Anim. sans Vertebr._ iii. 245.

[27] _Ibid._

[28] _Des Rapports généraux, &c. des Anim. invertebr. artic., Ann. du Mus._

[29] _Ibid._ _Hor. Entomolog._ 383.

[30] Leach in _Entomologist's Useful Compendium_, by Samouelle, 75.

[31] _Hor. Entomolog._ 348.

[32] _Ibid._ 354.

[33] _Ibid._ 373.

[34] _Ibid._ 381.

[35] _Ibid._ 389.

[36] There is some reason for thinking, though the octopod and myriapod insects breathe by tracheæ, that there is no small difference in the distribution of these organs. The _Trachean Arachnida_ have only a pair of spiracles, from which the tracheæ must _radiate_, if I may so apply the term, in order to convey the necessary supply of air to every part of the body. _Scutigera_, as far as I can discover, has only a _single_ series of _dorsal_ spiracles (see PLATE XXIX. FIG. 20)--an unusual situation for them: in these also, to attain the above end, each trachea must also radiate, so as to supply each part of the segment it is in. Those of _Iulus_, according to the observations of Savi (_Osservaz. per servire alla Storia di una Specie de Iulus_, &c. 15--), consist of bundles of parallel tracheæ. Perhaps these circumstances would warrant the considering of these _Arachnida_ and the _Myriapoda_ as primary classes? The genus _Galeodes_ is said to breathe by gills similar to those of the _Araneidæ_, which structure, probably, carries with it a system of circulation, and exhibits a _third_ type in the _Arachnida_, with four palpi, six legs, and a distinct thorax. This genus, then, is the corresponding point in the _Arachnida_ to the _Hexapod Aptera_, as the _Scorpions_ are to the _Cheliferidæ_ or Pseudo-Scorpions, and the _Araneidæ_ to the other _Octopods_; and these analogies furnish a strong proof, that the _Tracheans_ belong rather to _Insecta_ than _Arachnida_. Comp. _N. Dict. d'Hist. Nat._ xxvi. 445; and _Description de six Arachnid. nouv._ &c. par Leon Dufour, 16.

[37] Mr. MacLeay observes with regard to the _Tardigrade_, described by Spallanzani and Dutrochet, that "it proves that an animal may exist without antennæ or distinct annular segments to the body, but having two eyes and six articulate legs." (_Hor. Entomolog._ 350--.) Many _Acari_ prove the same thing. De Geer, vii. _t._ vii. _f._ 14.

[38] De Geer, vii. _t._ iii. _f._ 8.

[39] _Hor. Entomolog._ 351.

[40] De Geer, _Ibid._ 571, 583. _t._ xxxvi. _f._ 20, 21.

[41] Dufour _ubi supra._ _Hor. Entomolog._ 382.

[42] Male _Insecta_ in some instances engender more than once. Mr. MacLeay sen. has observed this with regard to _Chrysomela Polygoni_, and I have noticed it in _Bombyx Mori_.

[43] _Hor. Entomolog._ 134. 200.

[44] _Zoolog. Miscell._ iii. _t._ 146. In this figure the segments are made much more distinct than they are in my specimen.

[45] _Hor. Entomolog._ 422--.

[46] See above, VOL. I. 4th Ed. p. 66. Note^a.

[47] Surely the denomination ought to have been _Arachnido-Crustacea_, since the learned author considers them as belonging to the _Crustacea_ class.

[48] It may not be without use to give here a short definition of the _Annulosa_; I mean excluding the _Vermes_, which Mr. W. MacLeay has included; and the _Annelida_, which Latreille has made the fifth of his Annulose classes. _Ann. du Mus._ 1821.

_Annulosa._ Animal invertebrate, oviparous; external integument
of a firmer consistence than the internal substance,
serving as a general point of attachment to the
muscles; _eyes_ immoveable; _legs_ more than four,
jointed.

CLASSES.

1. _Crustacea._ Gills external; more than eight legs.
2. _Arachnida._ Gills internal; spiracles; eight legs.
3. _Insecta._ Tracheæ; spiracles; six to eight thoracic legs.

[49] What L. Dufour regards as the liver in _Scorpio_ (_N. Dict. d'Hist. Nat._ xxx. 421.) Treviranus looks upon as an Epiploon (_Fettkörper_) both in _Scorpio_ and _Aranea._ 6. _t._ i. _f._ 6. A A. _t._ ii. _f._ 24. _dd._ Hepatic ducts: _t._ i. _f._ 6. ii. _t._ ii. _f._ 24. β. β. β. β.

[50] _S. minutissima_ of Marsham is synonymous with _Dermestes atomarius_ De Geer, _Scaphidium atomarium_ Gyllenh., and _Latridius fascicularis_ Herbst., but surely arranging with none of these genera, being sufficiently distinguished from them and every other insect by its singular capillary wings. In my cabinet it stands under the name of _Trichopteryx_ K.

[51] Panz. _Fn. Germ. Init._ lxii. 24. Comp. _Hor. Entomolog._ Addenda, &c. 523.

[52] The _Annelida_ have, however, sometimes _jointed_ organs, which facilitate their progressive motion whether vermicular or undulatory; but they cannot be deemed legs, since they neither support the body nor enable it to walk, &c. Latreille _Anim. invertebr._ Artic. 126. _Ann. du Mus._ 1821.

[53] _De Antennis Insect._ ii. 65.

[54] _Nouv. Obs. sur les Abeilles_, ii. 376--. It appears from M. Huber's experiment, that it was only when the hair-pencil, impregnated with the oil of turpentine, was presented "près de la cavité, _au dessus de l'insertion de la trompe_," that the bee was sensible of the odour.

[55] _Anim. sans Vertebr._ I. i. Mem. i.

[56] PLATE VIII. FIG. 10-14; IX. FIG. 6-8.

[57] Coquebert _Illust. Ic._ iii. _t._ xxi. _f._ 3.

[58] _Hor. Entomolog._ 413--.

[59] _N. Dict. d'Hist. Nat._ xxviii.; compare 104 and 110.

[60] See above, VOL. I. Ed. 4. p. 63--.