Part 2

[14] I am fully aware that this part of the subject is far above the comprehension of man, and felt exceedingly reluctant to carry system farther than the two great groups--animals and vegetables; but alluding, as I am compelled to do so frequently, to the works of Mr. MacLeay, I was fearful lest my silence on this particular subject should be construed into consent. See _Horæ Entomologicæ_, p. 179.

To trace nature from the trivial differences which may distinguish between two kindred mosses--differences scarcely to be detected by the practised eye of the botanist--upwards to the grand grouping of organized matter, into kingdoms containing myriads of such species,--to define accurately major and minor divisions, and assign to each division, and each individual, its appropriate place in an enduring system, is a task, in all probability, far beyond the mental powers of any single individual, especially when we consider the interesting facts and fresh objects which are daily added to our store in such number as must convince the student that as yet he scarcely possesses a knowledge of one hundredth part of nature's works;[15] but, to pencil a dim and dubious outline,--to suggest whether nature has not aimed at such and such conclusions,--whether she has not chosen such and such paths, without making the slightest attempt to bend or turn her aside from her course where it does not precisely coincide with his own artificial schemes, may be fairly claimed as the privilege of any of her students, and ought to be freely granted to him by his fellow-labourers.

[15] In Britain we labour under another difficulty in this respect, a difficulty which has proved beyond measure mortifying during the progress of the present essay,--the want of a national museum.--A private individual cannot be expected to sacrifice all his time and money in procuring, preparing, and arranging, a tolerably perfect collection; a writer on natural history is, therefore, compelled to travel round to two or three hundred private collections, and solicit leave to make his memoranda. Few men of taste can regret the purchase of the ancient works of art now open to the public at the British Museum; but the immense sums of public money granted to that institution should insure the naturalist a similar treat with the artist. A collection of vertebrate and annulose animals should be immediately formed, arranged, and named after Cuvier, Latreille, or the most approved authority of the day. Among the insecta, I have no doubt a tolerably perfect--certainly, a very useful--collection might with little trouble be made from the specimens already in the Museum.

In looking for a centre around which to arrange the almost infinite hosts of the animal kingdom, the vanity of man naturally enough suggests himself; but to gratify this vanity, he must submit to the somewhat mortifying necessity of admitting six families of apes and monkies to his immediate company, and the tribe thus constituted may be termed Primates,--a name originally conferred on it by Linnæus. Anatomy, as well as external appearances, prove the propriety of this arrangement, however repulsive the idea may be to our false feelings of exclusiveness. Primates thus constituted, will be found to be the central seventh of a larger group, termed Mammalia by Linnæus; a group, which includes all the truly viviparous and mammiferous animals. Amongst the outermost of these, as we retrograde gradually from the type, man, we shall find a bird typified in the bat; a shark in the seal; many other fish in the whale; a tortoise, crocodile, and slender lizards, in the armadillos, ant-eaters, &c., all thus exhibiting a tendency to borrow characters from other approaching groups. Mammalia, thus surrounded, must of necessity be the central of seven groups, within the compass of which will be found all animals which possess a frame of connected bones and a spinal marrow; these are termed Vertebrata, and, I think, will be found to constitute a central seventh of all animated nature.

From this it will be apparent, that there are in nature forty-nine groups of animals, each of about the same value as Mammalia, as far as regards their relation to a whole. Distrustful of my own very limited knowledge of the subject, and fearful of encumbering science with crude theories and ill-defined divisions and characters which future discoveries may hereafter totally subvert, I shall content myself with observing, that I believe in the existence of such groups, and shall not presume to give them, at present, definitions or even names: the charge of ignorance is merited and easy to be borne, but the charge of attempting to establish divisions, in order to secure the paltry fame of naming them, I hope not to deserve.

In some instances, these tribes or sub-kingdoms seem pointed out by nature's self in so decided a manner, that the lisping infant will at once recognise them. Where this is the case, what can definition avail? Let us refer to birds as one of these clearly marked divisions. I single it out as better understood than either of the others. Let us ask, To what does all the arrangement tend which has here been so lavishly bestowed? To utter confusion, volume after volume, essay after essay, open their yawning leaves, and repeat, again and again, one and all, utter hopeless, unintelligible confusion. But if, neglecting the high authorities on the subject _in toto_, we condescend to consult nature, we shall soon perceive that birds readily range themselves in seven good and clearly defined groups; one of which is preeminently distinguished from the rest, and yet partakes in some one or other of its component genera of the characters of all the other groups; such a sub-class must, therefore, be central; and, by a little care in availing himself of the most obvious approaches, the naturalist will find every other sub-class, and order, and genus, beautifully filling up their appropriate situations, without causing any of those distortions which so disfigure every existing arrangement of this interesting tribe. Syrrhaptes, Serpentarius, and all those hitherto parodoxical creatures which seem to have frightened our ornithologists out of their wits, are now not only admissible, but absolutely necessary to connect tribes which no one had previously supposed in the least degree related;--but I will not here forestall, as an attempt to point out the numerous and unlooked-for relations existing among the genera of birds, which the present plan has served to develop, forms the subject of a separate essay, already in a state of forwardness; and the more immediate object of my present inquiry, although a tenant of the air, is not to be sought for among its feathered tribes. I will, therefore, leave these for the present, fully intending that the ornithologist as well as the entomologist shall have an opportunity of examining whether my theory has truth and reason to support it, or whether he must condemn it as an _ignis fatuus_ of the brain.

The law that rules animal rules also vegetable nature: the phænogamous plants present a centre very nearly corresponding, in relative value, to vertebrates among animals; these, again, offer equal scope for subdivision; and the surrounding vegetations must be those at present termed cryptogamous, which vary as greatly among themselves as they collectively do from the more perfect and central ones: the various tribes of Fungi, Algæ, Filices, Musci, &c., possessing wonderfully varied forms and characters, and assuming every size from the gigantic fern of the tropical islands to that almost invisible Mucor, which seems, by its instantaneous appearance, to be for ever floating in the air, prepared to vegetate wherever it may chance to fall, and has often afforded arguments to those who deny the dictum of _omnia ex ovo_, and support that of spontaneous reproduction; thus ennobling these almost nonentities, by assigning to them properties which man might pine for in vain, and which cannot be the attributes of dust.

The centre for each particular group will not always derive that mark of superiority from its size, or intelligence, or beauty, or complicated structure, but from a combination of these qualities, and more particularly from uniting in itself the principal and more decidedly distinguishing characters of the group of which it forms the nucleus, and the gradation will by no means be found to be regular, from the most perfect in the centre to the least perfect on the circumference of minor groups, although I imagine this relative position to obtain in the extremes: on the contrary, the approaches towards perfection or imperfection will be infinitely varied, presenting the most complete labyrinth of intricacies that imagination can conceive, yet all disposed with that beautiful and wonderful regularity which proclaims more loudly than words, that "the natural system is the plan of creation itself, the work of an ALL-WISE ALL-POWERFUL DEITY."[16]

[16] Horæ Entomologicæ, preface, p. xiii.

ON THE CLASSES OF INSECTA.

Many theories, which read plausibly enough, we find, on attempting to apply them, totally at variance with facts: I will, therefore, not content myself with making unsupported assertions, but endeavour to summon to my aid fragments of the great whole, and array them before the reader, in what I consider order, asking of him, as an especial favour, that he will examine and compare the genera and species which I shall mention as related to each other in corroboration of my scheme; for much as I could wish by argument to convince him that a system of circles, grouped in sevens, exists universally throughout nature, yet I should much prefer that, by actual experiment, he should convince himself. With this view I will take a rapid survey of the central class[17] of Insecta, observing in what particulars it is related to those which surround it. I have selected insecta first because I already possessed a slight knowledge of its contents; secondly, because there exists little difference of opinion as to those contents;[18] and, thirdly, because Mr. MacLeay has given it as his opinion "that it is among insects above all other groups of animals, that owing to their myriads of species, the mode in which nature's chain is linked--a mode, the knowledge of which comprises all knowledge in natural history, will be most evident, and therefore most easily detected."[19]

[17] I have invariably used the term class, to designate the orders of Linnæus, and sub-class, for the next division, of which seven are supposed to exist in every class: these sub-classes may sometimes constitute natural orders, in which case a plural termination is given; thus, Blatta constitutes in itself a sub-class Blatta, a natural order Blattæ, and a genus Blatta; but generally a sub-class will contain seven natural orders; as sub-class Scarabæus contains natural orders--Lucani, Coprides, Scarabæi, Histeres, &c.

[18] The only question as to the contents of insecta, is, whether the pediculi are true insects or not; the class Hemiptera is so closely related to them, that I cannot think it a great violation to place them in the outermost circle of that class; the acari may be supposed meeting them in an adjoining circle, but I have no desire to provoke controversy on this minor point.

[19] Annulosa Javanica, preface, p. xi.

It is somewhat remarkable that, although considerably upwards of two thousand years have elapsed since the first system of insects was promulged, at least the first of which we have any knowledge, yet no attempt has hitherto been successfully made to improve it; from this perfection I think we may fairly conclude, that the philosopher of Stagira was not merely a man of extraordinary talent, but that he had made himself the repository of what had previously been saved of the learning of his forefathers, in a day when it will be recollected the printing press had no existence; and we have nothing to prove that entomology had not degenerated through the two thousand years previous to Aristotle, as it unquestionably did during the two thousand years subsequent to the time of that philosopher, when our own immortal countryman, Ray, revived the science, and laid the foundation of a regenerated lustre, which, perhaps, may eventually rival that diffused by the great Stagirite himself. Be this as it may, the systematist has no choice but to go back two thousand years for the primary outline, or classification of insects; and, I may add, nothing but a desire to make myself clearly understood, prevents my adopting the nomenclature, as well as the division of Aristotle. I shall, however, employ the more modern and less appropriate names for the present, hoping that at a future day an opportunity may occur of doing justice to the merits of that writer, whom we are all compelled to follow, or to forsake the path of truth.[20]

[20] The learned authors of the _Introduction to Entomology_ have inserted a sketch of the Aristotelian system in that work, a reference to which will convince the reader that it is next to impossible for the entomologist to over-rate him. See _Introduction to Entomology_, Vol. IV. p. 433.

The reader who does not understand exactly what animals constitute the sub-kingdom Insecta, may refer to the _Introduction to Entomology_, where he will find the subject fully and accurately investigated.[21] It would be a needless incumbrance of my subject to repeat these definitions here, but as I am unable to meet with any characters for classes, by which relations and differences can readily and conveniently be traced, I have been induced to add a few definitions to those already in use, which I am the more willing to do because they will be useful here without ever perplexing science by forsaking the pages of this essay.

[21] Introduction to Entomology, Vol. III. pp. 1-51.

Column headings legend:

G: General character. R: Resemblance to Imago.

+---------------------+------------+----------+-----------+---------------+ | CLASSES | | LARVE | PUPA | IMAGO | | G | R | G | R | Wings. | Mouth. | |----------+----------+------------+----------+-----------+---------------| | I. LEPIDOPTERA. | | Polypod. | None. | Quiescent. | None. | Four, | Antliate. | | | | | | scaly. | | |----------+----------+------------+----------+-----------+---------------| | II. DIPTERA, _Arist._ | | Apod. | None. | Quiescent. | None. | Two, | Proboscidate. | | | | | | and two | | | | | | | poisers. | | |----------+----------+------------+----------+-----------+---------------| | III. HYMENOPTERA. | | Various. | None. | Quiescent. | Slight. | Four, | Mandibulate. | | | | | | membra | | | | | | | naceous. | | |----------+----------+------------+----------+-----------+---------------| | IV. COLEOPTERA, _Arist._ | | Various. | Various. | Quiescent. | Slight. | Two, | Mandibulate. | | | | | | and | | | | | | | two | | | | | | | wing | | | | | | | cases. | | |----------+----------+------------+----------+-----------+---------------| | V. ORTHOPTERA. | | Hexapod. | Perfect, | Active. | Perfect, | Four, | Mandibulate. | | | except | | except | structure | | | | in | | in | various. | | | | wanting | | wanting | | | | | wings. | | wings. | | | |----------+----------+------------+----------+-----------+---------------| | VI. HEMIPTERA. | | Hexapod. | Perfect, | Active. | Perfect, | Four, | Promuscidate. | | | except | | except | structure | | | | in | | in | various. | | | | wanting | | wanting | | | | | wings. | | wings. | | | |----------+----------+------------+----------+-----------+---------------| | VII. NEUROPTERA. | | Various. | Various. | Various. | Various. | Various. | Various. | +----------+----------+------------+----------+-----------+---------------+

The very imperfection of this table will constitute its principal utility, because, instead of acknowledging variety as a suitable definition of any particular part or state, the differences of which in respective classes, entomologists have been accustomed to consider characteristic, we find authors labouring to confine a group by what they would wish to consider good and solid characters, which characters they often at last leave so comprehensive, as not only to include the class which they had originally intended to define, but also a majority of those other classes which they had supposed previously disposed of. If, in reply, my reader should tell me that my seventh class was somewhat of this too comprehensive kind, I should simply reply that I intended it to be so; and if my reader happen to know a better, he can interline it in his copy. A space would then be occupied, which has hitherto in all such definitions been really, although not verbally, vacant.

It is hard to break through the trammels of habit; it is hard to give up what one has for a long time taken for granted; it is hard to relinquish favourite schemes, however untenable: an innovator, however, is bound to deliberate well and coolly,--is bound to try all the various schemes before him with the test of reason. If the entomologist do this he will find his positive knowledge much less than he expected,--he will perceive that he is book-wise and fact-foolish; if, therefore, he would wish to arrive at truth, he must strip himself of his borrowed garments and all the theoretical dogmas he may have, however incautiously, imbibed, and trust entirely to what he has discovered himself, or what has been discovered by those who had no theory to support but truth,--no end to answer but amusement; for your theoretical writers, if they meet with a fact which militates against a favourite theory, will too often suppress it entirely, and on the same principle are ever anxious to magnify to an unnatural size, any slight, and often imaginary, circumstance, which they consider may tell in their favour. Among theories that have been thus established on very weak and insufficient foundations are all dichotomous divisions, especially those in which one group is defined as possessing and the other as wanting any fixed and peculiar character; a definition, by the by, applicable to nearly all dichotomies: the dichotomy to which I have here to allude is the division of insects into Mandibulata and Haustellata. Now every division founded on the presence or absence of a particular character should be received with the greatest caution, because the second group in which the character is absent[22] is sure to be too comprehensive. Mr. MacLeay,[23] himself no great friend to dichotomies in general, is completely led away by this particular one. He considers the classes I. II. and VI. of the foregoing table to constitute one grand order, and the classes III. IV. V. and VII. to constitute another; and, after Clairville, he calls the former order, Haustellata, and the latter, Mandibulata. Mr. MacLeay's name is a tower of strength to any theory; and his authority, added to the plausibility of the idea, has really given such a truth-like appearance to this division, that we see it now universally adopted. Let us examine its worth. First, I would ask, Can distinctive characters, thus drawn from part only of the external anatomy of insects, be sound, when to enforce them we are compelled to neglect various other characters which we have been accustomed to consider all important? Scopoli has said, "_Classes et genera naturalia non sola instrumenta cibaria, non solæ antennæ nec solæ alæ constituunt_;" but our dichotomizing entomologists tell us, that neither antennæ, nor wings, nor habit, nor metamorphosis, are to be regarded at all, but "_sola instrumenta cibaria_;" at least, they infer this by separating Orthoptera and Hemiptera, by the intervention of several orders totally unrelated to either of them, a disruption which no nature-loving naturalist could for a moment admit. The truth is, there are seven kinds of mouth in insects, so distinct that good classes could be built on them,[24]--classes which would confirm those which Aristotle appears to have derived chiefly from other characters: of these seven, three are mandibulate, three are haustellate, and one without the rudiments of mandible or haustellum. The three which are mandibulate are somewhat similar, the three which are haustellate bear no more resemblance to each other than that which they all may be said to bear to that haustellated quadruped an elephant; and the tie which holds Haustellata together as a group is about as strong as one formed to bend in a genus Blaps mortisaga, Acrida aptera, Cimex lectularius, and the female of Bombyx antiquus, with the one sole character of being destitute of wings.

[22] And, be it observed, Haustellata merely means _not mandibulate_; it does not propose to assert that the contents of the tribe so named need have a particular kind of haustellate mouth, or any mouth at all.

[23] Mr. MacLeay has written a little pamphlet on the impropriety of the dichotomous system, which I recollect reading, when published, with considerable pleasure. I forget its title.

[24] If the reader happen to be unacquainted with the terms which I have used in characterizing the mouth, he will find them accurately and elaborately described in _Ind. to Ent._ Vol. III. p. 393, _et seq._ The orders of Fabricius depend entirely on the formation of the mouth. See _Systema Entomologiæ_.