1. Araneidea M^cL. (Aranea L., Araneidæ Latr.) The Araneidea, or spiders, seem resolvable into two suborders,—the Sedentaries and the Wanderers; thus forming, perhaps, what Mr. MacLeay would denominate the normal groups of a circle of Arachnida.

Def. Mandibles armed with a perforated claw.

Head and Trunk coalite.

Palpi pediform, anterior pair without claws.

Abdomen without segments or elongated tail.

Spiracles two[1251].

Anus furnished with an apparatus for spinning[1252].

2. Scorpionidea M^cL. (Scorpio L. Latr.)

Def. Mandibles chelate.

Head and Trunk coalite.

Anterior Palpi chelate[1253].

Posterior Palpi pediform.

Pectens two[1254].

Abdomen divided into segments and terminating in a jointed tail, armed at the end with a sting[1255].

Spiracles four pairs.

3. Galeodea.

Def. Head distinct[1256].

Eyes two.

Mandibles chelate with dentated chelæ.

Palpi pediform, the anterior pair thickest with a retractile sucker.

Trunk consisting of two principal segments, with a minute supplementary posterior one[1257].

Spiracles two placed in the trunk[1258].

Pseudo-pectens two[1259].

Abdomen divided into segments.

Anus unarmed and without a spinning apparatus[1260].

4. Phrynidea.

Def. Mandibles unguiculate.

Anterior Palpi chelate or unguiculate[1261], very robust.

Posterior Palpi pediform, very long and slender.

Abdomen divided into segments.

Spiracles two pairs.

Anus terminating in a mucro, and sometimes in a filiform jointed tail without a sting at the end.

v. Having considered the Orders into which Insecta and Arachnida may be divided, I am next to give you some account of the groups into which each is further resolvable. To draw out, however, a complete scheme of these would be deviating from my province, and extend this letter to an enormous length. Indeed, to give the natural primary and subordinate sections of every Order, would require a knowledge of the subject to which no Entomologist has yet attained. I shall therefore only say something general upon them, and refer you to an example of each kind of group.

Previously to the groups themselves their nomenclature claims our attention. M. Latreille in his last arrangement of Annulose animals has divided his Orders into Sections; Families; Tribes; and Genera: his tribes he has often further subdivided into lesser sections, represented by capital and small letters, &c.[1262]. Mr. MacLeay, discarding the term section, has Tribes; Races (Stirps); Families; Genera, and Subgenera[1263]. But as in descending from the Order to the lowest term, or the species, a series of groups gradually diminishing in value, which require a greater number of denominations than have yet been employed by Entomologists, often occur, I think we may with benefit to the science add to the list. I would therefore propose the following primary and subordinate divisions of an Order: 1. Suborder; 2. Section; 3. Subsection; 4. Tribe; 5. Subtribe; 6. Stirps; 7. Family; 8. Genus; 9. Subgenus. I would further propose that each of these successive groups should have a name always terminating alike, so that the value of the group when spoken of might always be known by the termination:—thus if a subclass end in ata, a suborder might end in ita; a section in ana, a subsection in ena; a tribe in ina, a subtribe in ona; a stirps in una; and a family in idæ; the genera being left free.

With regard to their characters, we are not to place our groups upon Procrustes' bed, and lop or torture them to accommodate them to every standard we may have fixed for them: assuming one set of characters for suborders, another for tribes, and so for every other group; for the value of characters varies,—those that in some cases are common to an Order, in others indicate only sections, or tribes, or genera and species, or sometimes even sexes. What is constant in one group is not so in another, and vice versâ; so that it is a vain labour to search for a universal character. If it is our wish really to trace the labyrinth of nature, we can only accomplish it by a careful perusal and examination of her various groups. It is singular how much and how far various Entomologists, and those of the very highest class, have been misled by a kind of favouritism to give too universal a currency to certain characters for which they have conceived a predilection. Some have been the champions of the antennæ; others of the trophi; others again of the wings; and others of the metamorphosis. These are all characters which within certain limits lead us right, and are an index to a natural group; but if we follow them further, we leave the system of nature, and are perplexed in the mazes of a method[1264].

Let us now see whether we can pitch upon any suborder which will afford an example of every group that we have lately named. Mr. MacLeay, from a consideration of the larvæ of that Order, has divided the Coleoptera into five primary groups that may be denominated Suborders. Whether these are all natural groups has not yet been made sufficiently evident. It answers my present purpose, however, to assume it as proved. I select therefore his Chilopodimorpha for my suborder, altering the name as above proposed to Chilopodimorphita: for my Section I take the Predaceous beetles, or Adephaga of M. Clairville, distinguished by having the upper lobe of their maxillæ biarticulate and palpiform;—these I would denominate Adephagana, or devourers. They consist of two groups forming two subsections, the one terrestrial and the other aquatic; which I would name, following Mr. MacLeay, Geodephagena and Hydrodephagena. These two subsections are each resolvable into two Tribes constituted by Linné's four genera Cicindela and Carabus; Dytiscus and Gyrinus. The first tribe, remarkable for the swiftness of their flight, I would name Eupterina, or fliers; the second, equally noted for running, Eutrechina, or runners; the third Eunechina, or swimmers; and the fourth Gyronechina, or swimmers in a circle. The second of these groups, the Eutrechina, are resolvable into two other groups or Subtribes; one distinguished by having the cubit or anterior tibia notched, (which, from their being in general not very brilliant in colour, I would call Amaurona, or obscure); the other having the cubit without a notch, (which, from the brilliancy of many of them, I would name Lamprona, or splendid). These subtribes are both further resolvable into two or more races (Stirpes). I select that to which the crepitant Eutrechina belong, containing those which from their usually truncated elytra MM. Latreille and Dejean have named Truncatipennes[1265]: these, to shorten the name, I call Truncipennuna. This brings us down to the lowest group formed out of genera and subgenera: or the family, which from its principal genus is named Brachinidæ, and which leads us to the genus Brachinus, and the subgenus Aptini. Thus we get the following scale, expressing every division of an Order, till we arrive at its lowest term, or the species that compose it.

Suborder
Chilopodimorphita M^cL.
Section
Adephagana Clairv.
Subsection
Geodephagena M^cL.
Tribe
Eutrechina
Subtribe
Amaurona
Stirps
Truncipennuna Latr.
Family
Brachinidæ
Genus
Brachinus
Subgenus
Aptini.

In the construction of this scale I have endeavoured to steer clear of being led by any system, but, with the exception of the Suborder, which I assume, to resolve it into natural groups gradually decreasing in value, or tending to the lowest term, which appear all of them to have been considered as such by preceding Entomologists. The four Tribes into which the two subsections Geodephagena and Hydradephagena appear resolvable, are not only distinguished by the characters of the perfect insect, but likewise by those of their larvæ, which are constructed on four distinct types; those of the Gyronechina being the most perfectly Chilopodimorphous of the whole, and those of the Eunechina the least so[1266]. The former appear rather to form an osculant tribe, or one without the circle, than one within it; and to be going off towards another section, including Hydrophilus, Sphæridium, &c. I must observe, that between Dytiscus and Hydrophilus there is a striking agreement both in their form and habits in the larvæ[1266], and even in several characters in the perfect insect; so as in many respects to generate a doubt whether they ought not to enter the same circle and to follow each other. Yet the change of habits in the latter, which from a carnivorous larva becomes a herbivorous beetle; the consequent change of structure in their oral organs, their antennæ, and other striking differences; and the evident intervention of the Gyronechina and some other osculant tribes between the two, forbid their union in one and the same circle.

vi. I need not say more on those larger groups of an Order which conduct us to what are denominated its genera; but upon these last it will not be a waste of your time to enlarge a little. In the last edition of the Systema Naturæ, and in its appendixes, Linné has described 2840 species of Insecta and Arachnida, which he divided into 83 genera, allowing upon an average nearly 35 species to each genus. From the paucity of the materials, therefore, of which his system was constructed, there was no loud call upon him for numerous genera. But now more than thirty times that number are said to have found a place in the cabinets of collectors[1267], and there is good reason for thinking that perhaps half that are in existence are as yet undiscovered;—this makes it a matter of absolute necessity to subdivide the Linnean genera, which in fact, with regard to the majority of them, were the primary groups of his Orders, rather than an approximation to the ultimate. But this principle may be carried too far: for it is the nature of man to pass from one extreme to the other: and this seems to me to be the case when it is proposed to make genera the extreme term of subdivision before you arrive at species. But it is argued by a very acute Zoologist, that simplicity, perspicuity, and room for necessary variations are best preserved by distinguishing these subdivisions each by an appropriate name[1268]:—Granted. But still it is only a choice of evils. It would require probably more than 10,000 names to designate them, were every extreme group distinguished by a name: but if Mr. MacLeay's admirable pattern exhibited in his genus Phanæus[1269] were followed, it would not call for more than 2000—could the trifling difficulty occasioned sometimes by the discovery of a new group, be set against the advantage of having only 2000 names to commit to memory instead of 10,000[1270]? But if, after all, it is judged best to name subgenera, M. Savigny's excellent plan of distinguishing them by a plural termination would diminish the weight of the above objection, and might be used with advantage.

When the component parts of any minor group differ from another,—for the most part in important characters, indicating some tangible difference in their habits and economy, and confirmed by peculiarities in their larvæ; and these differences run through the whole, except that as usual they grow weaker as it is passing off to another; especially where they are striking in the centre or type of the group,—this is always a legitimate genus: but where the characters assumed are very slight, and nothing peculiar in its habits, economy or larva, warrant such distinction, it ought not to be conferred.

vii. I must next say a word concerning species and varieties. A species is a natural object whose differences from those most nearly related to it had their origin when it came from the hands of its Creator; while those that characterize a variety, have been produced since that event. As we do not know the value and weight of the momenta by which climate, food, and other supposed fortuitous circumstances operate upon animal forms, we cannot point out any certain diagnostic by which in all cases a species may be distinguished from a variety;—for those characters that in some are constant, in others vary. In general, where there is no difference in form, appendages and organs, sculpture, proportions and larvæ,—colour alone, especially in insects inhabiting the same district, only indicates a casual variety. Thus Aphodius luridus has sometimes pale elytra with the striæ black (Scarabæus nigro-sulcatus Marsh.): at others it has black spots between the striæ, as in the type: in a third variety the elytra are black at the base and pale at the apex (Sc. varius Marsh.); and lastly, in a fourth they are intirely black (Sc. gagates Marsh.);—yet all these in every other respect precisely correspond. But the converse of this will scarcely hold good; for doubtless minor differences of structure are sometimes produced by a different food and climate: which may probably account for some variations observable in the individuals apparently of the same species obtained from different countries.

Having considered the kind and value of the groups into which Annulose animals, and more especially insects, may be divided, I shall next call your attention to their composition. There are five numbers and their multiples which seem more particularly to prevail in nature: namely, Two—Three—Four—Five and Seven. But though these numbers are prevalent, no one of them can be deemed universal. The binary number, which affords the most simple, and for that reason perhaps not the least valuable, mode of arrangement, we see exemplified when two branches, so to speak, diverge from a common stem,—as in the Vegetable and Animal kingdoms; the terrestrial and aquatic Predaceous beetles; in the thalerophagous and saprophagous Lamellicorn ones; in the Anoplura and Thysanura; the Chilopoda and Chilognatha amongst Apterous insects; in the Scorpionidea and Aranidea amongst the Arachnida; and in the Macrura and Brachyura amongst the Decapod Crustacea. Again, in other cases three seems to be the most prominent number: this takes place sometimes with regard to the primary groups of an Order, or what I denominate the Suborders. Thus we have the Diurnal, Crepuscular, and Nocturnal Lepidoptera[1271]; the Linnean genera Blatta, Mantis, and Gryllus constitute the Orthoptera; and other instances of this number might be produced in some minor groups. But that which appears to prevail most widely in nature is what may be called the quaterno-quinary; according to which, groups consist of four minor ones; one of which is excessively capacious in comparison of the other three, and is always divisible into two; which gives five of the same degree, but of which, two have a greater affinity to each other than they have to the other three[1272]. Mr. W. S. MacLeay, in the progress of his inquiries to ascertain the station of Scarabæus sacer, discovered that the thalerophagous and saprophagous Petalocerous beetles resolved themselves each into a circle containing five such groups. And having got this principle, and finding that this number and its multiples prevailed much in nature, he next applied it to the Animal Kingdom in general: and from the result of this investigation, it appeared to him that it was nearly, if not altogether, universal[1273]. Nearly at the same time a discovery almost parallel was made and recorded by three eminent Botanists, MM. Decandolle, Agardh, and Fries, with regard to some groups of the Vegetable Kingdom[1274]; and more recently Mr. Vigors thinks he has discovered the same quinary arrangement in various groups of birds[1275]. This is a most remarkable coincidence, and seems a strong argument in favour of Mr. MacLeay's system. I should observe, however, that according to that system, as stated in his Horæ Entomologicæ, if the osculant or transition groups are included, the total number is seven[1276]:—these are groups small in number both of genera and species, that intervene between and connect the larger ones. Each of these osculant groups may be regarded as divided into two parts, the one belonging to the upper circle and the other to the lower; so that each circle or larger group is resolvable into five interior and two exterior ones, thus making up the number seven. Though Mr. MacLeay regards this quinary arrangement of natural objects as very general, it does not appear that he looks upon it as absolutely universal,—since he states organized matter to begin in a dichotomy[1277]: and he does not resolve its ultimate groups into five species; nor am I certain that he regards the penultimate groups as invariably consisting of five ultimate ones. In Copris I seem in my own cabinet to possess ten or twelve distinct types[1278]; and in Phanæus, the fifth type, which Mr. MacLeay regards as containing insects resembling all the other types[1279], appears to me rather divided into two; one formed by P. carnifex, Vindex, igneus, &c., and the other by P. splendidulus, floriger, Kirbii, &c.

The great point which demands our attention in considering a numerical arrangement of the Kingdoms of Nature is the value of the component members of each group. It is by no means difficult to divide a Kingdom, a Class, or an Order into two, or three, or five, or seven or more groups, according to any system we may be inclined to favour; but it is not so easy to do this so that the groups shall be of equal rank. Yet it seems requisite that in grouping our objects, as we descend towards the lowest term we should resolve each only into its primary elements, and of them form the next group; and so on till we come to species. When I say of equal rank, I do not mean an exact parity between the members into which a group is primarily resolvable,—because there will always be a degradation in descensu from the perfection of the type; but merely that parity (to use a metaphor) that there is between children of the same mother, differing in their relative ages and approach to the perfection of their nature. Perhaps it may be observed with respect to the quinary system, that this condition is not complied with, since two of the groups taken per se appear really to form one group; or to be much nearer to each other than to the remaining groups. But when it is taken into consideration that this great group, always resolvable into two, is the typical group, and that the two are really equal, or rather superior in value to the three others, the objection seems to vanish.

With regard to all numerical systems we may observe, that since variation is certainly one of the most universal laws of nature, we may conclude that different numbers prevail in different departments, and that all the numbers above stated as prevalent are often resolvable or reducible into each other. So that where Physiologists appear to differ, or think they differ, they frequently really agree.

II. The Almighty Creator, when he clothed the world that he had made with plants, and peopled it with animals, besides the manifestation of his own glory, appears to have had two most important purposes in view;—the one to provide a supply for the mutual wants of the various living objects he had created, for the continuance of the species, and for the maintenance of a due proportion, as to numbers, of each kind, so that all might subserve to the good of the whole; and the other, that by them he might instruct his creature man in such civil, physical, moral and spiritual truths, as were calculated to fit him for his station in the visible world, and gradually prepare him to become an inhabitant of that invisible one for which he was destined. The first of these purposes was best promoted by creating things "according to their kind," with sexes monœcious or diœcious; that groups of beings related to each other, and agreeing in their general structure, might discharge a common function. This we see to be the case generally in nature; for where there is an affinity in the structure, there is usually an affinity in the function. The last,—or the instruction of man in his primeval state of integrity and purity,—was best secured by placing before him for his scrutiny a book of emblems or symbols, in which one thing either by its form or qualities, or both, might represent another. If he was informed by his Creator that the works of creation constituted such a book, by the right interpretation of which he might arrive at spiritual verities as well as natural knowledge, curiosity and the desire of information concerning these high and important subjects would stimulate him to the study of the mystic volume placed before him; in the progress of which he would doubtless be assisted by that Divine guidance, which even now is with those who honestly seek the truth. Both divines and philosophers have embraced this opinion, which is built upon the word of God itself[1280].

This last purpose of the Creator was the root of the analogies, connecting different objects with each other that have no real affinity, observable in the works of creation: so that from the bottom to the top of the scale of being, there is many a series of analogous forms, as well as of concatenated ones; and the intire system of nature is representative, as well as operative: it is a kind of Janus bifrons, which requires to be studied in two aspects looking different ways. To what degree of knowledge the primeval races of men attained after the fall, by the contemplation and study of this book of nature, we are no where informed; but we learn from the highest authority that the revelation that God thus made of himself was in time corrupted, by those that professing themselves to be wise became fools, to the grossest idolatry, which sunk men in the lowest depths of sensuality, vice, and wickedness[1281].

In no country was this effect more lamentably striking than in Egypt, whose gods were all selected from the animal and vegetable kingdoms.

This species of idolatry doubtless originally resulted from their having been taught that things in nature were symbols of things above nature, and of the attributes and glory of the Godhead. In process of time, while the corruption remained, the knowledge which had been thus abused was lost or dimly seen. The Egyptian priesthood perhaps retained some remains of it; but by them it was made an esoteric doctrine, not to be communicated to the profane vulgar, who were suffered to regard the various objects of their superstitious veneration, not as symbols, but as possessed of an inherent divinity: and probably the mysteries of Isis in Egypt, and of Ceres at Eleusis, were instituted, that this esoteric doctrine, which was to be kept secret and sacred from the common people, might not be lost.

But this kind of analogy is of a higher order than that of which I am here principally to speak,—that, namely, which the various objects of nature bear to each other. This, however, though of a lower rank, is essentially connected with the other, and leads to it; for it establishes the principle, that created things are representative or symbolical: and we find, when we view them in this light, that as we ascend from the lowest beings in the scale of creation, we are led from one to another till we reach the summit or centre of the whole, and are thus conducted to the boundaries of this visible and material system; from whence we may conclude that we ought not here to stop, but go on to something invisible and extra-mundane, as the ultimate object intended to be reflected from this great speculum of creation—the Creator himself, and all those spirits, virtues, and powers that have emanated from him.

The analogies which the various objects of the animal kingdom mutually exhibit, have for the most part been either overlooked by modern Physiologists, or have been mistaken for characters that indicate affinity; a circumstance that has often perplexed or disrupted their systems. Dr. Virey appears to have been one of the first who obtained a general idea of the parallelism of animals in this respect[1282]; and M. Savigny has contrasted the Mandibulata and Haustellata of the insect tribes as presenting analogies to each other[1283]. But a countryman of our own (often mentioned with honour in the course of our correspondence), peculiarly gifted by nature, and qualified by education and his line of study for such speculations, and possessing moreover the invaluable opportunity of consulting at his ease one of the first Entomological cabinets in Europe, in a work that will for ever couple his name with the science that he cultivates[1284],—has first taught the Naturalist the respective value and real distinctions of the two kinds of relationship that I am now discussing. He has opened to the philosopher, the moralist and the divine, that hitherto closed door by which our first parents and their immediate descendants entered the temple of nature, and studied the symbols of knowledge that were there presented to them: and in addition to his labours (in numerous respects successful), in endeavouring to trace out the natural groups of beings connected by affinity, has pointed out how they illustrate each other by analogy; thus affording, as was before observed[1285], a most triumphant reply to the arguments of those modern sophists, who, from the graduated scale of affinities observable in creation, were endeavouring to prove that animals, in the lapse of ages, were in fact their own creators[1286].

For the more satisfactory elucidation of the subject before us, I shall consider, first, how we are to distinguish affinities from analogies; and then mention some of the various instances of the latter that occur between insects and other animals, and between different tribes of insects themselves.

To know what characters denote affinity and what are merely analogical, it must be kept in mind that the former being predicated of beings in a series (whether that series has its gyrations that return into themselves, or proceeds in a right line, or assumes any other intermediate direction, it matters not), it cannot be satisfactorily ascertained but by considering attentively the gradual approximation or recession of the structure to or from a certain type in any point of such series. If, therefore, you wish to ascertain whether the characters, in which any given object resembles other objects in certain groups, indicate affinity or only analogy, you must first make yourself acquainted with the common features which distinguish the animals known to belong to that group,—either those relating to their structure, or to their habits and economy. If the object under your eye partakes in these characters more or less, in proportion as it approaches the type or recedes from it, the relation it exhibits is that of affinity; but if, though it resembles some members of it in several points of its structure, it differs from the whole group in the general features and characteristic marks that distinguish it, the relation it bears to those members is merely that of analogy. Thus, for instance, Ascalaphus italicus in its antennæ, the colouring of its wings, and its general aspect, exhibits a striking resemblance to a butterfly; yet a closer examination of its characters will satisfy any one that it is in quite a different series, and has no affinity whatever to that genus. A departure, however, in only one respect from what may be called the normal characters of its group, does not annul the claim of any tribe of insects to remain in it; since this very often only indicates a retrocession from the type, and not a disruption of its ties of affinity. Thus the saw-flies (Serrifera) differ from the other Hymenoptera, though not in their pupæ, yet more or less in their larvæ; but this alone cannot countervail their agreement with that Order in their organs of manducation and motion, in their ovipositor, and in the other details of their structure[1287].

I have on a former occasion pointed out many of the analogies which take place between insects and other parts of the animal kingdom, and even between insects and the mineral and vegetable kingdoms[1288]: I shall now resume the subject more at large, but without recurring to those last mentioned. In considering the analogies which connect insects with other animals, or which they exhibit with respect to each other, we may have recourse to two methods. We may either consider them as placed somewhere between the two extremes of a convolving series, from which station we may trace these analogies upwards and downwards towards each limit; or we may conceive them and other animals in this respect arranged in a number of series that are parallel to each other, in which the opposite points are analogous. The first mode will perhaps best explain the analogies that exist between insects and other animals, and the last those between different groups of insects themselves. I shall give an example or two of each method, beginning with the first.

There are two tribes in the animal kingdom that seem placed in contrast to each other, both by their habits and by their structure. One of these is carnivorous, living by rapine and bloodshed, and can seldom be rendered subservient to our domestic purposes; while the other is herbivorous or granivorous, is quiet in its habits, and easily domesticated. Amongst insects we find the representatives of both: those of the first tribe are distinguished by their predaceous habits, by the open attacks, or by the various snares and artifices which they employ to entrap and destroy other insects. They may usually be known by their powerful jaws or instruments of suction; by their prominent or ferocious eyes; by the swiftness of their motions, either on the earth, in the air, or in the water; by their fraud and artifice in lying in wait for their prey. Amongst the Coleoptera, the Predaceous beetles,—including the Linnean genera Cicindela, Carabus[1289], Dytiscus, and Gyrinus,—are of this description; and they symbolize those higher animals that by open violence attack and devour their prey:—for instance, the sharks, pikes, &c., amongst the fishes; the eagles, hawks, &c., amongst the birds; and the whole feline genus amongst the beasts. Similar characters give a similar relation of analogy to the Mantidæ and Libellulina amongst the Orthoptera and Neuroptera. The whole family of Arachne, the larvæ of the Myrmeleonina, &c., portray those animals that to ferocity add cunning and stratagem, or suck the blood of their victims. The Myriapods symbolize in a striking manner the Ophidian reptiles. Look at an Iulus, and both in its motions and form you will acknowledge that it represents a living serpent; next turn your eyes to a centipede or Scolopendra, and you will find it nearly an exact model of the skeleton of a dead one, the flat segments of its body resembling the vertebræ, its curving legs the ribs, and its venomous maxillæ the poison-fangs. The great body of the Orthoptera, the Homopterous Hemiptera, the Lepidoptera, and Trichoptera, afford no example of Predaceous insects. All the analogies I have here particularized, ascending from the insect, terminate in races of a corresponding character and aspect amongst the Mammalia, and thus lead us towards man himself, or rather to men in whose minds those bad and malignant qualities prevail, which, when accompanied by power, harass and lay waste mankind; and thus ascending from symbol to symbol, we arrive at an animal who in his own person unites both matter and spirit, and is thus the member both of a visible and invisible world: and we are further instructed by these symbols,—perpetually recurring under different forms,—in the existence of evil and malignant spirits, whose object and delight is the corporeal and spiritual ruin of the noble creature who is placed at the head of the visible works of God.

The other tribe of animals that I mentioned of a milder character, may be looked upon as represented by many herbivorous, or not carnivorous, insects; amongst others, the Lamellicorn beetles imitate them by their remarkable horns, so that they wear the aspect of miniature bulls, or deer, or antelopes[1290], or rams, or goats, whether these horns are processes of the head or of the upper jaws. The gregarious Hymenoptera, some of which form part of our domestic treasures, may be regarded in some degree as belonging to this department. From insects the ascent upwards, with regard to form, is by some of the branchiostegous fishes, which symbolize the horns of cattle; with regard to character, by the various species of Cyprinus and other similar genera.—Whether any of the reptiles may be looked upon as falling into this division, I am not sufficiently conversant with them to assert; but if any, the Chelonians, or tortoise and turtle tribes, are entitled to that distinction. Amongst the birds, the Gallinæ and Anseres,—from which Orders we derive our domestic poultry, whether terrestrial or aquatic,—and our game, form the step next below the ruminants, or cattle: and we are thus again led towards man, and are symbolically instructed in those domestic and social qualities which endear us to each other, best promote the general welfare, and render us most like good spirits and the Divinity himself; of whom the perpetual recurrence of animals exhibiting these amiable and useful qualities is calculated to impress upon us some notion. I might mention many more instances of ascending analogies; as from some of the Diptera by the parrots, to the Quadrumanes or monkey tribes—or from some of the Iulidæ that roll themselves into a ball, to the Armadillo; but these are sufficient to set your mind at work upon the subject, so that you may trace them for yourself. Nor shall I occupy your time by pointing out how analogies may be traced from insects downwards towards the lowest term in the scale of animal life, but proceed to consider the analogies observable between insects themselves; in which I shall follow the second method lately mentioned, and consider them as arranged in parallel series.

In studying the analogies that take place between insects themselves, we should always bear in mind that our inquiry is not concerning an affinity which demands a correspondence in various particulars that are not necessary to constitute an analogy; as, for instance, that there should be a mutual imitation in all the states of any two insects. Wherever we discover a marked resemblance between two perfect insects, there is a true analogy, though their metamorphosis may differ; and where there is not that resemblance, though the metamorphosis may agree, there is no analogy. In fact, insects are sometimes analogous in their first state and not in their last; and at other times analogous in their last and not in their first; but the analogy is most perfect when it holds in all their states: it then, indeed, almost approaches to an affinity. They may also be analogous to each other in their habits and economy, when there is little or no resemblance in their form; and, vice versa, be analogous in their form and not in their habits. So that different sets of analogies may be assumed as foundations for different systems. Thus Mr. MacLeay assumes the metamorphosis as the basis of analogy between the corresponding Orders of Mandibulata and Haustellata[1291], while M. Savigny compares the perfect insects[1292]: the result therefore differs in some instances. I shall now lay before you in a tabular view their plans and my own.

Savigny.

MacLeay.

In these two last columns, you see, I differ little from M. Savigny: I merely exclude the Aphaniptera as forming an osculant Order, and I have added the Coleoptera and Heteropterous Hemiptera for reasons I shall soon assign. From Mr. MacLeay I differ more widely, which has resulted from our different ideas as to the mode of tracing analogies; his theory leading him to the metamorphosis, and mine leading me[1293] to the perfect insect, for the foundation of our several systems. It remains that I show how each of the pairs in my columns represent each other: but I must observe, that the analogies exhibited by insects in the corresponding Orders of these columns are not equally striking in all their respective members; but only in certain individual species or genera, more or less numerous, by which the nearest approach is made to the contrasted forms.

To begin with the Coleoptera and Heteropterous Hemiptera.—Both are distinguished by having an ample prothorax, a conspicuous scutellum, the neuration of their wings, the substance of the hard part of their hemelytra, which, as in Coleoptera, sometimes imitates horn and sometimes leather, and is occasionally, like elytra, lined with a hypoderma[1294]; the articulation of the head with the trunk is likewise the same in both[1295]: and some Heteropterous species so strikingly resemble beetles (Lygæus, brevipennis &c.), having little or no membrane at the end of their hemelytra, that they might easily be mistaken for them. These circumstances prove, I think, that this suborder is more analogous to the Coleoptera than to the Orthoptera, with which it agrees in scarcely any respect but its metamorphosis. The counterparts of this last Order indeed, instead of the Heteropterous, are to be sought for amongst the Homopterous Hemiptera, various species of which exhibit a most marked and multifarious analogy with numerous Orthoptera. Many of both Orders (Cicada, Locusta), as you have heard long since, are signalized by possessing the same powers of song, and produced by an analogous organ[1296]: a large proportion also of both are endued with wonderful saltatorious powers, and their posterior tibiæ are similarly armed; their legs in general likewise are longitudinally angular, and the head in both articulates with the trunk in the same manner[1297]. In both Orders too, the upper organs of flight are most commonly tegmina, but sometimes in both they are nearly membranous, like wings. In Centrotus and Acrydium, the one Homopterous and the other Orthopterous, the front is bilobed, the eyes are small; there are only two stemmata between the eyes; the prothorax is conspicuous, and behind is producted into a long scutelliform process, under which all the parts also are analogous; the abdomen articulates with the trunk in the same way, is similar in shape in both, and consists of short inosculating segments. Some Fulgoridæ and Truxalides agree also in their producted front. Other analogous characters might be named between these tribes, but these are sufficient to confirm M. Savigny's opinion. That the Neuroptera present analogies to the Lepidoptera, though they differ so widely from them in their metamorphosis and habits, is evident from the instance lately adduced of Ascalaphus italicus, which was described as a butterfly by Scopoli[1298]; and many of the Libellulina, by their wings, partly transparent and partly opaque, and by the shape of those organs and of their bodies, imitate the Heliconian butterflies: and this resemblance is much more striking than any that occurs between the perfect insects in the Neuroptera and Homopterous Hemiptera. With regard to the Hymenoptera and Diptera the analogy is undisputed, and must strike every beholder; and one would almost say it was a real affinity, were it not that the resemblance is not only general between Order and Order, but that almost every Hymenopterous tribe has its counterpart amongst the Diptera; the saw-flies[1299] for instance, the ichneumons, the various false-wasps[1300], the false-bees[1301], the bees, the humble-bees, the ants, &c., severally find there a representative that wears its livery and general aspect: a circumstance which evidently proves that it was part of the plan of the Creator to place them in contrast with each other. Were I to pursue this subject further, it might not be difficult to show that were the tribes of Mandibulata or of Haustellata also arranged in columns, analogies would be discoverable between their corresponding points: this seems to be Mr. MacLeay's opinion[1302]; and it is worth your pursuing the subject further, which cannot but prove very interesting.

But though the general analogy of these columns is that of Order to Order, yet individual species in each Order sometimes find their representatives in a different one from that with which they generally are contrasted;—thus some Diptera, as Culex, by the scales on the veins and other parts of their wings, are analogous to Lepidoptera rather than Hymenoptera[1303]; as is also the genus Psychoda by its form.

We come now to the consideration of a question not easy to be decided,—I mean, which Order of insects is to have the precedency, and which is the connecting link that unites them to Vertebrate animals.

Linné (and Mr. MacLeay seems in this to coincide with him) considered the Coleoptera as at the head of the Class of insects; De Geer thought the Lepidoptera entitled to that honour; Latreille and Cuvier begin with the Aptera: Marcel de Serres favours the Orthoptera[1304]; and others, on account of their admirable economy, have made the Hymenoptera the princes of the insect world[1305]. If the claim to priority was to be decided by the exquisiteness of instincts and the benefits conferred upon the human race, doubtless it would be in favour of the last-mentioned insects. If the power to do mischief carried it, and to lay waste the earth, the Orthoptera would be entitled as much as any to the bad pre-eminence. If beauty, and grace, and gaiety, and splendour of colours were the great requisite, and the law enjoined, Detur pulchriori,—the Lepidoptera would doubtless win the throne. But if perfection and solidity of structure, as they ought, are to regulate this point; we must, I think, with the illustrious Swede, assign the palm to the Coleoptera. If we consider these in all their parts, the organs for flight only excepted, they seem more perfectly formed and finished than the insects of any other order. But which of the Coleopterous tribes are entitled to the precedency? Linné placed the Lamellicorn beetles at the head of the order, beginning with the Dynastidæ, probably led by some characters which seem to connect these with the Branchiostegous fishes. In this he was followed by Fabricius. But Latreille and most modern Entomologists have begun with Cicindela and the other Predaceous beetles. I am not certain what are Mr. MacLeay's sentiments on this subject; but from what he says in the Annulosa Javanica[1306], it does not appear that he is a convert to the latter opinion. Bulk and strength seem the most striking characteristics of the former tribe, which represent the cattle or ruminants amongst Vertebrate animals.—Strength united with agility and a considerable portion of grace and symmetry evidently confers a degree of pre-eminence upon the latter, symbolizing the feline race, which seems to throw no small weight into their scale.

There are two Classes of Vertebrate animals with which insects may appear to claim kindred. The fishes, and the reptiles. Fishes in their fins exhibit no small resemblance to insects; the pectoral and ventral ones representing their arms and legs, and the dorsal ones their wings: Pegasus Draco in this last respect is not unlike a butterfly[1307]. In some genera (Ostracion, Pegasus, &c.), like insects the animal is covered with a hard shell or crust, formed by the union of its scales. The oral cirrhi of many fishes seem analogous to the palpi of insects; and in some a pair longer than the rest represent their antennæ[1308]. Another circumstance in which insects and fishes correspond, is the wonderful variety of forms, often in the greatest degree eccentric, that occurs in both Classes. Some of the cyclostomous fishes, as Ammocœtus, Gastrobranchus, are supposed to connect the fishes with the Annulosa, by means of the Annelida as an osculant Class[1309], which Mr. MacLeay regards as the passage to the Chilopoda[1310]: his Mandibulata he considers as passing into the Anoplura by means of some osculant Order as yet unknown[1311]. But I must confess I can see no good ground for this last transition:—the Anoplura appear much more nearly related to the Psocidæ, especially by the apterous Atropos pulsatoria[1312] than to any Coleopterous insect. But having stated these opinions, I shall leave you to draw your own conclusions, as the question is still perplexed with many difficulties. I am ready to admit that some Vertebrates approach near to the Annelida; but that it is through them alone that they are connected with insects, is not at present clear.

With regard to reptiles, they seem to be connected with insects by several characters. In the Chelonians, the skeleton merges in the external carapace or shell; the Ophidians change their skin like larvæ; the Batrachians undergo metamorphoses; some of the Saurians also have their changes: and the Draco volans has wings somewhat analogous to those of insects[1313]. Were I to be asked what Order of insects could connect with reptiles, I should point to the Orthoptera, especially Gryllus L., which by their noise and saltatorious powers not a little resemble frogs; and the larvæ of some strikingly imitate their form[1314]: and of others even that of a lizard[1315]. But these resemblances, after all, may only indicate analogies.