Part 29

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.

MANDIBULATA. HAUSTELLATA.

Neuroptera } { Lepidoptera _Ascalaphus_ } { _Papilio_

Hymenoptera } { Diptera _Eucera_ } { _Tabanus_

Orthoptera } { Homoptera _Locusta_ L. } { _Cicada_

Aptera } { Aphaniptera _Nirmus_ } { _Pulex_.

MACLEAY.

MANDIBULATA. HAUSTELLATA.

Trichoptera Lepidoptera Hymenoptera Diptera Coleoptera Aptera Orthoptera Hemiptera Neuroptera Homoptera.

K. AND S.

Coleoptera Hemiptera _Leach_ Orthoptera Homoptera _Leach_ Neuroptera Lepidoptera Hymenoptera Diptera.

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.

FOOTNOTES:

[1126] _Philos. Botan._ 97. n. 153.

[1127] _Ibid._ 98. n. 155, &c.

[1128] Μεθοδος is rendered "An _artificial_ and compendious mode of doing any thing; a mode of _teaching_ or _learning_:" Μεθοδευω is "To overcome by _artifice_." Συσεμα applied to music is "A _full_ and _harmonious_ assemblage of tones." So that in fact, _System_ should express the actual disposition of objects, or a _Natural_ arrangement; and _Method_, an _Artificial_ one.

[1129] Wisdom. xi. 20.

[1130] Genes. i. 31.

[1131] W. S. MacLeay in _Linn. Trans._ xiv. 54.

[1132] Linn. _Syst. Nat._ i. 11.

[1133] Qu. Whether every real species or group has not some one or more _peculiar_ characters which it neither derives from its predecessor nor imparts to its successor in a series?

[1134] _Œuvres_ vii. 51--.

[1135] _N. Dict. d'Hist. Nat._ xx. 485.

[1136] VOL. III. p. 11--.

[1137] W. S. MacLeay. _Hor. Entomolog._ passim; and in _Linn. Trans._ ubi supr. 53--.

[1138] _N. Dict. d'Hist. Nat._ xx. 485.

[1139] The idea of a continuous _series_ militates somewhat against that of a circle returning into itself. The progression of the series may be in a circle; but at the point of contact where the second circle meets the first, the lines must cut each other; and at this point of intersection of the two circles are of course the osculant groups constituting the first and the last of each circle, which in their intervention come in contact with each other, or rather forming _transition_ groups. If each circle is regarded as _absolute_, the _series_ is broken, though the osculant groups connect the circular ones.

[1140] Mr. MacLeay almost admits that there are _natural_ genera. _Hor. Ent._ 492.

[1141] _Œuvr._ vii. 52.

[1142] _N. Dict. d'Hist. Nat._ ii. 34--.

[1143] Even those animals that like the _Spongiæ_ and _Alcyonia_ are aggregate, and fixed by a common base, have a partial degree of voluntary locomotion in their cells.

[1144] VOL. III. p. 10.

[1145] Cuv. _Anat. Comp._ i. 173.

[1146] _N. Dict. d'Hist. Nat._ ii. 25.

[1147] _Ibid._ 26--.

[1148] VOL. III. p. 12--.

[1149] _Hor. Entomolog._ 200--. See above, p. 3--.

[1150] Savigny _Mém. sur les Anim. sans Vertèbr._ II. i. 3.

[1151] MacLeay _Hor. Ent._ 204.

[1152] VOL. III. p. 46--, See above, p. 247.

[1153] See above, p. 195--.

[1154] VOL. II. p. 306--.

[1155] In this respect insects excel many reptiles, which can reproduce some of their parts.

[1156] See MacLeay _Hor. Entomolog._ 203, 206--. 298--.

[1157] Linn. _Philos. Botan._ n. 155, 160.

[1158] VOL. III. LETTER XXVIII.

[1159] Scias Characterem non constituere Genus, sed Genus Characterem; Characterem fluere e Genere, non Genus e Charactere; Characterem non esse ut Genus fiat, sed ut Genus noscatur. _Philos. Botan._ m. 169.

[1160] VOL. I. p. 66. note^a.

[1161] VOL. III. p. 417.

[1162] Derived from κολεος, _a sheath_, and πτερον, _a wing_.

[1163] _Hist. Animal._ l. iv. c. 7. l. v. c. 20.

[1164] Ὁσα το πτερον εχει εν κολεῳ.

[1165] Latr. _Gen. Crust. et Ins._ i. 169. Oliv. _Ins._ i. Introd. v.

[1166] VOL. I. p. 65.

[1167] In some genera, as _Molorchus_, &c., they do not completely cover the wings. PLATE X. FIG. 1. PLATE I. FIG. 4, 5.

[1168] In _Buprestis_, _Molorchus_, &c., they are only longitudinally folded.

[1169] PLATE X. FIG. 4.

[1170] From σρεψις, _a turning or twisting_, and πτερον.

[1171] VOL. III. p. 589. note^c.

[1172] _Hor. Entomolog._ 371--.

[1173] _Linn. Trans._ xi. 96--.

[1174] _Ibid._ _t._ ix. _f._ 1. d.

[1175] PLATE II. FIG. 1.

[1176] _Linn. Trans._ Ibid. _f._ 15. b.

[1177] From δερμα, _a skin_.

[1178] PLATE X. FIG. 5.

[1179] From ορθος, _straight_.

[1180] _Fn. Suec._

[1181] From δικτυον, _a net_.

[1182] See above, p. 266.

[1183] From νευρον, _a nerve_.

[1184] _Her. Entomolog._ 433.

[1185] VOL. III. p. 563.

[1186] Ibid. p. 125--.

[1187] Ibid. p. 423, 441--, 451, 454--.

[1188] Ibid. p. 656.

[1189] See above, p. 186--.

[1190] _N. Dict, d'Hist. Nat._ x. 344.

[1191] The ovipositor of _Raphidia_ seems merely calculated to introduce its eggs under bark; it seems incapable of boring.

[1192] From ὑμην, _a membrane_.

[1193] De Geer ii. 1035.