Having already discussed the general history of butterflies at considerable length, in a volume devoted to the illustration of the kinds found in Britain, it is not our intention to resume the subject in this place, further than to make a few remarks on certain peculiarities presented by many foreign species, a selection from which forms the subject of the present volume.

The remarkable superiority in size and beauty of most tropical productions over those of temperate regions, is scarcely more strikingly exemplified in any department of nature than in this. The most richly ornamented of our native species, and we possess many of great beauty, appear insignificant when contrasted with those of Brazil and Eastern Asia. Various as are the modifications of form which they present in this country, we find nothing to prepare us for the peculiar outline and aspect which many kinds assume in the warmer regions of the earth. Here we seldom find any having the hinder wings prolonged into a tail, but among foreign species this is a common appendage, sometimes long and linear, at other times broad and spatulate; and occasionally there are not fewer than three or four on each of the hinder wings. Along with this variety of outline, they exhibit almost every possible shade of colour, from the most brilliant to the most obscure, combined and blended in the most elegant and harmonious designs, rendering this tribe of creatures one of the most ornamental to be found in nature.

Although such endless diversity of colouring is observable in this class as a whole, it is, at the same time, worthy of remark, that most of the principal groups are characterized by the prevalence of particular hues, as well as considerable uniformity in their mode of distribution; that is to say, certain modifications of structure are generally accompanied with a certain pictorial design. Thus, the greater proportion of the genus Pieris are white; Colias and Callidryas various shades of yellow, from the palest sulphur-yellow to deep reddish-ochre. Argynnis is almost invariably fulvous or reddish brown, variegated with numerous undulating black lines or spots; the under side more or less ornamented with silvery streaks and spots. In the species of the European genus Thais, the wings are spotted or chequered with black and red. The prevailing colour in the genus Argus is azure-blue. Danais, IdÆa, and Euploea, have this character in common, that the breast and head are always punctured with white. In Cethosia, hieroglyphical markings cover the under side of the wings in such a manner as is observable in no other genus.

Many of the caterpillars of exotic butterflies offer peculiarities in their forms and appendages, of which we find no prototype in the kinds occurring in Britain. In the place of spines, some have the body thickly covered with long fleshy prominences, of a corneous consistency at the tip, and probably serving as a means of defence. In others, spines of singular conformation and formidable size are thickly stuck over the whole surface, making it resemble a miniature forest. A few are provided with a long anal horn, resembling that which is so conspicuous in the caterpillars of the Sphinges. If Madam Merian’s delineation of the larva of Urania Leilus be correct (which there is now reason to believe is the case), it bears many slender spines, as long as the whole body, and as stiff as iron wire. Another species (that of Papilio Protesilaus), is likewise clothed with plumose spines, two of which at the hinder extremity are much longer than the rest, and terminate in an appendage like a star. Equally remarkable with any of these is the caterpillar of one of the NymphalidÆ (Adoleas Aconthea), which has a series of long filiform bodies projecting from each side, thickly clothed laterally with hairs of considerable length diminishing gradually to the extremity, which is armed with a few minute spines.

As might be expected, great diversity likewise prevails in the appearance of the chrysalides; but to these it will be more convenient hereafter to refer, in the preliminary notices to the respective genera. One of the most remarkable, however, may be mentioned, that of Morpho Menelaus, which has the nasal prominence of the prothorax produced into a long curved horn, which extends to the middle of the abdomen. In another species of the same group, the head is obtuse, projects considerably, and is curved upwards at the extremity, exactly like the beak of an ancient galley.

Our acquaintance with the geographical distribution of the diurnal lepidoptera was long very imperfect, and it may yet be said to be very far from complete. The older naturalists seem to have been but little alive to the importance of the subject, and even if it had been otherwise, the means they possessed for illustrating it were comparatively limited. Those who had opportunities of collecting specimens in foreign countries, valued them merely as specimens, and, in general, kept no record of their localities, or natural history properly so called. Collections from China and the East Indies were indiscriminately mixed, in their way homewards, with others from the Cape of Good Hope; and American species were in like manner mingled with such as are proper to the West Indian islands. Hence it followed, that Fabricius and others were so often led into error when they indicated the native country of the kinds they described: but, indeed, the author just named did not very frequently attempt this, but merely says, “From the Indies”—an expression which means nothing more explicit, in his acceptation of it, than that the species in question is exotic. LinnÆus, also, when he uses the same word, means indiscriminately either the East or West Indies. The indications of localities in modern works are in general copious and accurate, but they have not hitherto been made the basis of any general and satisfactory view of the distribution of the species.

As might be expected in the case of animals endowed with considerable power of flight, certain kinds of diurnal lepidoptera have a much more extensive range than most other insects—than the coleoptera for example. It is now ascertained that Cynthia cardui, a species well known throughout Europe, (without confounding it, as may sometimes have been done, with the kindred species C. Hunteri), occurs in Senegal, Egypt, Barbary, Cape of Good Hope, in the islands of Bourbon and Madagascar, in Bengal, China, Java, New Holland, Brazil, and North America; so that it may be called a complete cosmopolite. Of the four quarters of the globe, Europe is poorest in these insects; and next to it is Africa. Asia, including the great islands of the Indian Archipelago and America, are both exceedingly rich. Of the former, the islands seem to be much more prolific than the continent; they are the exclusive haunts of the gigantic Ornithoptera, several of the largest and most richly coloured of the Pierides, as well as several of the most remarkable species of the genus Morpho. South America produces a greater number than any other country; and Brazil, always preeminent for its exuberance both in animal and vegetable life, may be said to be the richest portion of the new continent. It has been estimated by an individual who has enjoyed the advantage of personally examining the country, that Brazil alone affords between 600 and 700 species of diurnal lepidoptera, a calculation which seems in no degree overcharged. Among these are many genera peculiar to America, such as Heliconia, Castnia, Erycina, &c. In almost every one of its physical properties, Africa affords a complete contrast to the country just named; and however favourable its arid soil, and far-extending deserts of parched and drifting sand, may be to the existence of certain peculiar races of coleoptera, it is by no means generally adapted to the support of creatures which derive their entire sustenance from vegetable juices. The sea-coast, and umbrageous banks of the larger rivers, however, are pretty abundantly supplied, and afford many species peculiar to the country. This is the metropolitan station of the genus Acrea, and it is likewise inhabited by several peculiar groups of the genera Papilio, Pieris, &c. The neighbouring island of Madagascar is much richer than the continent, and exemplifies what has been observed in relation to many other islands, that their zoological productions by no means correspond to those of the nearest portion of the main land. Little relation exists between the diurnal lepidoptera of Madagascar and the Cape of Good Hope, but a very close one can be traced between the former and those inhabiting distant parts of the continent, such as Senegal and Sierra Leone. Mauritius and Bourbon likewise differ considerably in their lepidopterous productions from Madagascar. In the latter, magnificent Papilios, AcrÆÆ, EuploeÆ, Danaides, UraniÆ, Cyrestes, and Xanthidia, embellish by their elegant forms and splendid colours, the marshy and pestilential forests of that extensive island, and rival in beauty that majestic and teeming vegetation which has always excited the admiration of botanists22. New Holland is not without its peculiar species, although this department of its zoology is not characterised by such marked singularities as are observed among its higher animals and vegetable productions.

A singular circumstance has been recorded by a recent traveller regarding one of the species, Euploea humata (Mac Leay), found in the country just referred to, namely, that it is employed as an article of food!

He states that there is a certain mountain, called the Bugong Mountain from multitudes of small moths, named Bugong by the natives, which congregate at certain times upon the masses of granite which compose it. The months of November, December, and January are quite a season of festivity among these people, who assemble from every quarter to collect these moths. They are stated also to form the principal summer food of those who inhabit to the south of the Snow Mountains. To collect these moths (improperly so called, for as above indicated, they are true butterflies), the natives make smothered fires under the rocks on which they congregate; and suffocating them with smoke, collect them by bushels, and then bake them by placing them on heated ground. Thus they separate from them the down and the wings; they are then grounded and formed into cakes, resembling lumps of fat, and often smoked, which preserves them for some time. When accustomed to this diet, they thrive and fatten exceedingly upon it23. Millions of these butterflies were likewise observed on the coasts of New Holland, both by Captains Cook and King; and thus, says Mr. Kirby, has a kind Providence provided an abundant supply of food for a race that, subsisting entirely on hunting and fishing, must often be reduced to great straits24.

These insects were, no doubt, the first that attracted the attention of naturalists, in consequence of their imposing appearance and striking metamorphoses. Collections of them began to be made at an early time, and were valued not only by the lover of nature, but by those who had no farther or more worthy design in view than to possess them as objects highly ornamental. Very extensive collections exist in nearly all the principal cities and museums of Europe; and many are to be found throughout Britain, not only belonging to public institutions for promoting natural history, but also in the possession of private individuals. One of the best conditioned collections of exotic lepidoptera in this country, is that in the possession of the East India Company, made in Java by Dr. Horsfield. As the method followed by that gentleman for preserving his specimens was attended with great success, the following account of it will be interesting and useful to those who have opportunities of making collections in foreign countries:—“During the inquiries I made,” says Dr. Horsfield, “in the early part of my residence in Java, to become acquainted with the best methods for securing what I obtained in my excursions, I noticed the plan described by Le Vaillant in his Travels in Africa, for the preservation of entomological collections. It is the following:—Boxes or chests carefully made of light wood, of a convenient portable size, are provided with partitions or moveable shelves, each consisting of a simple board; these are fitted at the distance of two inches one from another, in grooves in the sides of the box, in which they are made to slide with accuracy and facility, and are therefore removable at pleasure. These boards or shelves have necessarily the exact dimensions of the ends of the chest, and are placed in a vertical position; a small vacancy is preserved between this lower extremity and the floor, and any object detached by accident falls to the bottom without causing further injury. Each board or shelf, lined with cork or soft wood, supplies, in some measure, the place of a cabinet drawer. When taken out of the box and placed on a table, it rests securely, and affords a plain surface, upon which insects may be fixed and examined with perfect ease and security: it is returned into the box in an instant, which, if carefully made, when closed secures most effectually the contents. A small quantity of camphor, at the bottom, spreads its influence over the whole. One large box may conveniently contain fourteen boards, answering the purpose of as many drawers; and, being eighteen inches long, they have a manageable size. This plan I resolved to adopt. In the early period of my pursuits, the boxes which I provided were made of light wood, and to their use I must ascribe, in a great measure, the preservation of my collection. I found that they afforded a complete protection against the ants and other destructive insects which abound in the island of Java, perhaps as much as in any other tropical region. They were peculiarly useful in travelling, and possessed the advantage of affording a ready access to the subjects. As the ultimate object of my pursuits was to provide an extensive and well-conditioned collection, which might be useful and instructive in England, I had, soon after receiving the patronage of the Honourable East India Company, directed my attention to the provision necessary for its safety during a voyage. My residence at Surakarta afforded me peculiar advantages in this point of view. Both materials and workmen are here obtained, perhaps more readily than in any other part of Java. Boxes, according to the plan described, were therefore provided, of more substantial materials than those employed in travelling, in proportion to the increase of the collection. The wood of the Bombax pentandrum was employed for lining the boards and securing the pins; and I ascribe to an acquaintance with the peculiar property of this wood—which renders it an effectual substitute for cork—the preservation of the collection during its transportation. After having carefully packed the subjects, every necessary precaution that suggested itself was used in securing the boxes against accidents during the voyage. They were individually painted and covered with oil-cloth. Each box was then placed in an outer case, made of the same substantial materials, and secured in the same manner. By these various precautions, and by the care which the collection received from the commander of the vessel during the voyage, I enjoy the satisfaction of having brought the whole in safety to England25.”

The systematic arrangement of this tribe of insects has always been considered a task of great difficulty. So convinced of this was Latreille, who had himself studied the subject profoundly, that he says a classification of lepidoptera may be considered the touchstone of entomologists. This difficulty arises chiefly from the uniformity of organization which prevails throughout the order—a uniformity occasioned by all of them being designed to subsist on liquid food, and to imbibe it in the same manner. The oral organs, therefore, which are of the first importance in classifying other tribes—the coleoptera, for example, in which they undergo almost endless variations of form and consistency to fit them for consuming every kind of organic substance, from semi-fluid animal or vegetable matter to the hardest ligneous tissue—are, in this instance, of comparatively little avail. Recourse must be had to secondary and subordinate characters; and even when we are convinced that, owing to a peculiar facies, and the concurrence of many minute resemblances, certain groups should be regarded as distinct, it is found difficult to define them in a satisfactory manner. Neither has the difficulty been much lessened by the manner in which the subject has been handled by many modern naturalists. The numerous illustrations of lepidoptera published of late years, have been partial, being either selections from the whole class, or forming part of a local fauna. In either case, the subject is regarded in too insulated a light. The illustrator of foreign butterflies selects a species, and by giving prominence to all its minute characters, proposes it with considerable plausibility as a distinct genus. The local faunist divides his groups in reference to his own limited sphere of observation. Neither contemplates the possibility of being ever called upon to elaborate a general system, and he leaves it to those who are to reconcile all existing inconsistences. Hence it follows, that so many of the genera proposed in local and partial works can find no place in a general one; for however specious they may appear when standing alone, it is often found that they will not unite into a consistent whole, and they may therefore be said still further to embroil the very subject they were designed to elucidate.

The Linnean distribution was vague and unsatisfactory, even at the time when it was first produced, and soon became utterly inapplicable when the amount of known species was increased. But it did not fail to exercise, like every other system emanating from that gifted mind, a powerful influence on the progress of the science, and is interesting on account of its ingenuity and poetical elegance. “It is an attempt,” says Dr. Shaw, “to combine, in some degree, natural and civil history, by attaching the memory of some illustrious ancient name to an insect of a particular cast.” The first LinnÆan division consists of Equites, which are distinguished by the shape of the upper wings; these are longer, measured from their posterior angle to their anterior extremity, than from the same point to the base; the antennÆ sometimes filiform. The equites are denominated Troes or Trojans, distinguished by having blood-coloured spots on each side of the breast: or Achivi, Greeks, which are without red marks on the breast, of gayer colours, and having an eye-shaped spot on the anal angle of the inferior wings. The second division consists of Heliconii, which are distinguished by having the wings narrow and entire, often naked or without scales; the superior oblong, the inferior very short. The third division consists of the Danai, so called from the sons and daughters of Danaus. They are divided into Danai candidi, or such as have whitish wings, and Danai festivi, in which the ground colour is never white, and the surface variegated. The fourth division consists of the Nymphales, distinguished by the edges of the wings being scolloped or indented; it is subdivided into N. gemmati, in which the wings are marked with ocellated spots, and N. Phalerati, without these spots. The fifth division contains the Plebeii. These are commonly smaller than the preceding butterflies, and are subdivided into rurales and urbicolÆ; the former having the wings marked with obscure spots, the latter for the most part with transparent spots.

In his earlier works, Mantissa and Species, Fabricius made no important change on the LinnÆan method; but the many additional species which had come to his knowledge when he drew up his Systema glossatarum, led him to establish many new genera, and remodel the arrangement of the old ones. This method consists of forty-one genera, most of which have been adopted by subsequent authors; but it is less complete than it might otherwise have been rendered, owing to the death of the author before it was finished. Latreille did not deviate materially from the Fabrician method, adopting nearly all the genera; but he did not derive the distinctive characters exclusively from the antennÆ and palpi, as the Danish entomologist had done, but had recourse to other parts of structure, and likewise judiciously took into account the peculiarities of the caterpillar and chrysalis. Several arrangements were proposed subsequent to or contemporaneous with that of Latreille, such as those of Lamarck, Dumeril, Dalman, &c. but most of them are of little importance. The last mentioned individual, however, appears to have been the first to apply to actual practice, in his description of the lepidoptera of Sweden, characters derived from the neuration of the wings, the value of which were first pointed out by Mr. Jones, in a paper in the LinnÆan Transactions, published in 1794. Godart, without appearing to have been acquainted with what had been done by Dalman, likewise had recourse to the structure of the wings in his arrangement, as published in the EncyclopÉdie Methodique, and Lepidoptera of France. In the latter work, the diurnal series is classified with reference to the appearance of the discoidal cell in the inferior wings; and by adopting this excellent character, he has, in most instances, greatly improved on Latreille’s method.

In 1776, an arrangement was proposed which attracted little attention at the time, but which has since risen to considerable distinction. It is that exhibited in the Systematic Catalogue of the Lepidoptera found in the neighbourhood of Vienna, by MM. Denis and SchiffermÜller. This original and highly valuable system is entirely founded on the appearance of the caterpillars. It is singular that characters almost exclusively drawn from that state, should confirm the classifications founded on characters afforded by the imago or complete insect. But to such a degree does this coincidence obtain, that almost all the families proposed by the Austrian naturalists have been adopted as genera by those who were guided by other principles. This method remained for a long time almost unknown to the naturalists of this country, and even on the continent its excellence seems to have been but inadequately appreciated, except among the Germans. The only authors that have acted upon it are Ochsenheimer, and his continuator Treitschke, in their valuable and extensive work on the Lepidoptera of Europe26.

But there can be little doubt that those arrangements are the most accurate and philosophical which are founded on characters derived from all the different states in which these insects exist. This conviction seems now to be generally entertained, and most writers of very recent date have seen the propriety of acting upon it. In the works of Curtis, Stephens, Horsfield, &c. it has been adhered to to a greater or less extent, and in a general work on Lepidoptera lately published by Dr. Boisduval of Paris, nearly equal importance is assigned to the peculiarities of the caterpillar, chrysalis, and butterfly. As this method presents some new features, and is the last that has been laid before the public, we shall give an account of it along with the accompanying remarks in the authors own words:—“It is not till after a most attentive study of the butterflies of Europe in their different states, and after having collected a certain number of materials on the metamorphoses of exotic species, that we have attempted to group the lepidoptera in a manner different from that hitherto followed, not neglecting, at the same time, the study of those authors who have occupied themselves with this order, that we might be enabled to combine the results of their labours with our own. We do not flatter ourselves, however, that the combinations which we have made are altogether free from blame, any more than those of our predecessors. When occupied with the productions of a single country, the classification is much more easy; the greater number of species associate pretty well with each other, and, if we except a few of the most anomalous, a series is obtained free from much irregularity. In this way, the European species form a pretty homogeneous assemblage, and the same thing holds with regard to those of South America, New Holland, or any other country taken by itself; but when we attempt to classify those of the whole globe, we frequently meet with intermediate genera which interrupt this harmony. If we even take a somewhat numerous genus belonging at the same time to several different countries, we find species which form a passage to other races proper to each of these countries. For example, the genus Pieris of Latreille offers species in America (genus Leptalis) which bear a perfect resemblance to the Heliconii in their colour, the length of their bodies, and narrowness of the wings. Others of the same country (genus Euterpe) insensibly unite with that division of American Papiliones which is of a black colour with red spots; those of Europe, on the contrary, present certain relations to Parnassius, Pieris CratÆgi appearing to form the passage to P. Mnemosyne, while those of India gradually approach Colias through P. Judith and P. Panda, and to Danais with green spots through P. Valeria. All other genera of some extent, and distributed over several countries, are in the same condition.

“What we have just stated, applies equally to the correlation of species with each other. If we take, for example, the genus Satyrus of Latreille, we perceive that it is composed of an infinite number of secondary groups, scarcely any of which are proper to one country. Thus, in Europe, we have the division to which Galatea belongs, extending along the basin of the Mediterranean, even into Persia; that of Hermione, which takes the same direction, and continues to Cachmere; that of Norna, proper to the polar regions of the two continents; that of Nigres, which inhabits mountainous countries, and is found only at the Cape and at Chili; finally, that of the Satyres, properly so called, which are connected with the species of New Holland, some of them with those of Chili, of North America, and Siberia. America and the East Indies, likewise, present groups which in general appearance differ widely from our European species; while there are others which resemble several at the same time. A collection of the Satyres of one country would, therefore, form a sufficiently natural series; but it would appear most irregular when the species of several countries were brought together.

“Our method is partly founded on the caterpillar, and partly on the perfect insect. We attach the greatest importance to the caterpillar state, and the characters which it furnishes have often more value in our estimation, than those afforded by the butterfly; but generally these characters confirm each other, in other words, two caterpillars presenting the same characters produce flies which likewise partake of the same generic characters. It will no doubt be objected to us, that it is illogical to deduce characters except from the animals we are attempting to classify. We reply, that by following any other plan we must despair of attaining to a natural method. Besides, it is not necessary to be acquainted with the caterpillars of every species; it is sufficient to study a caterpillar and chrysalis of Vanessa or Pieris to have an exact idea of those of the two genera. Even though it should be very difficult to verify the characters taken from the larva, this is no reason why we should abstain from employing them. It is not merely from the fruit that botanists obtain their characters, but likewise from the flower, and even from the first developement of the vegetable embryo. The flower is to the plant what the caterpillar is to the lepidopteron, and the different modes of metamorphosis have as much value as those of inflorescence.

“It appears to us that Latreille’s three divisions, taken from LinnÆus—Diurnal, Crepuscular, and Nocturnal—are too inaccurate to be retained, especially the crepuscular section. The denomination Diurnal not only applies to all the known kinds of day butterflies, but also to an almost infinite number of others forming a part of the two other divisions, such as Macroglossa, Zygenides, CastniariÆ, Ægocerides, &c. That of Crepuscular is adapted more or less to some sphinges, but by no means to the Zygenides, which fly only in the heat of the sun. Finally, the term Nocturnal is not more properly applicable to all the species, since many belonging to this section appear only during the day. In order to avoid these improper denominations, we have substituted for the word Diurnal, that of Rhopaloceres, proposed by M. Dumeril. Being unable to perceive limits between the Crepuscular and Nocturnal divisions of Latreille, we have united those two great sections under the name of Heteroceres. In our method, therefore, the lepidoptera are divided into two grand legions, Rhopaloceres and Heteroceres27.”

Dr. Boisduval then proceeds to explain that the first of these divisions is characterised by antennÆ thickening to a club at the extremity; and the second, by having these organs variously shaped; this indeed is implied by the words themselves. The first division is subdivided into three sections, according to the manner in which the caterpillars transform themselves into chrysalides. Such as undergo this change by attaching themselves by the tail and a band round the middle, form the first division, named Succincti; such as are suspended by the tail only, the second, Penduli; while those which form a cocoon by rolling leaves together, compose the third division, termed Involuti.

Each of these three sections is then divided into tribes, according to characters derived from the caterpillars and the perfect insect. Among those furnished by the latter, the most important are considered to be the number of ambulatory legs and the form of the palpi. The genera are characterised by the form of the caterpillar and chrysalis, by the dispositions of the nervures of the wings, the form of the antennÆ, legs, palpi, thorax, &c. of the perfect insect.