Page images
PDF
EPUB

over with scales and spangles of metallic green, deepening occasionally into blue or golden or deep red spots. Others again have spots and markings as of molten silver or gold, while several lave changeable hues, like shotsilk or richly-coloured opal. The form of the wings, again, often attracts attention. Tailed hind-wings occur in almost all the families, but vary much in character. In some the tails are broadly spoon-shaped, in others long and pointed. Vany have double or triple tails, and some of the smaller species have them immensely clongated and often elegantly curled. In some groups the wings are long and narrow, in others strongly falcate ; anil though many fly with immense rapidity, a large number slutter lazily along, as if they had no enemies to fear and therefore no occasion to hurry.

The number of species of butterflies inhabiting any one locality is very variable, and is, as a rule, far larger in America than in the Eastern hemisphere; but it everywhere very much surpasses the numbers in the temperate zone. A few months' assiduous collecting in any of the Malay islands will produce from 150 to 250 species of butterflies, and thirty or forty species may be obtained any fine day in good localities. In the Amazon valley, however, much greater results may be achieved. A good day's collecting will produce from forty to seventy species, while in one year at Para about 600 species were obtained. More than 700 species of butterflies actually inhabit the district immediately around the city of Para, and this, as far as we yet know, is the richest spot on the globe for diurnal lepidoptera. At Ega, during four years' collecting ;

NICI

Mr. Bates obtained 550 species, and these on the whole surpassed those of Para in variety and beauty. Mr. Bates thus speaks of a favourite locality on the margin of the lake near Ega :-“The number and variety of gaily-tinted butterflies, sporting about in this grove on sunny days, were so great, that the bright moving flakes of colour gave quite a character to the physiognomy of the place. It was impossible to walk far without disturbing flocks of them from the damp sand at the edge of the water, where they congregated to imbibe the moisture. They were of almost all colours, sizes, and shapes; I noticed here altogether eighty species, belonging to twenty-two distinct genera. The most abundant, next to the very common sulphuryellow and orange-coloured kinds, were about a dozen species of Eunica, which are of large size and conspicuous from their liveries of glossy dark blue and purple. A superbly adorned crcature, the Callithea Markii, having wings of a thick texture, coloured sapphire-blue and orange, was only an occasional visitor. On certain days, when the weather was very calm, two small gilded species (Symmachia Trochilus and Colubris) literally swarmed on the sands, their glittering wings lying wide open on the flat surface.” 1

When we consider that only sixty-four species of butterAlies have been found in Britain and about 150 in Germany, many of which are very rare and local, so that these numbers are the result of the work of hundreds of collectors for a long series of years, we see at once the immense wcalth of the cquatorial zone in this form of life.

| The Naturalist on the Amazone, 2nd edit. p. 331.

Immeuse

а

2010

Peculiar IIabits of Tropical Butterflies.—The habits of the butterflies of the tropies offer many curious points rarely or never observed among those of the temperate zone. The majority, as with us, are truly diurnal, but there are some Eastern Vorplidæ and the entire American family Brassolidæ, which are crepuscular, coming out after sunset and flitting about the roads till it is nearly dark. Others, though flying in the daytime, are only found in the gloomiest recesses of the forest, where a constant twilight may be said to prevail. The majority of the species fly at a moderate height (from five to ten feet above the ground) while a few usually keep higher up and are difficult to capture ; but a large number, especially the Satyrida, many Erycinidae, and some few Nymphalida, keep always close to the ground, and usually settle on or among the lowest herbage. As regards the mode of flight, the extensive and almost exclusively tropical families of Heliconidæ and Danaidæ, fly very slowly, with a gentle undulating or floating motion which is almost peculiar to them. Many of the strong-bodied Nymphalidæ and Hesperidæ, on the other hand, have an excessively rapid flight, darting by so swiftly that the eye cannot follow them, and in some cases producing a deep sound louder than that of the humming-birds.

The places they frequent, and their mode of resting, are various and often remarkable. A considerable number frequent damp open places, especially river sides and the margins of pools, assembling together in flocks of hundreds of individuals ; but these are almost entirely composed of males, the females remaining in the forests where, towards the afternoon, their partners join them. The majority of butterflies settle upon foliage and on flowers, holding their wings erect and folded together, though early in the morning, or when newly emerged from the chrysalis, they often expand them to the sun. Many, however, have special stations and attitudes. Some settle always on tree-trunks, usually with the wings crect, but the Ageronias expand them and always rest with the head downwards. Many Nymphalidæ prefer resting on the top of a stick; others choose bushes with dead leaves ; others settle on rocks or sand or in dry forest paths. Pieces of decaying animal or vegetable matter are very attractive to certain species, and if disturbed they will sometimes return to the same spot day after day. Some IIesperida, as well as species of the genera Cyrestis and Symmachia, and some others, rest on the ground with their wings fully expanded and pressed closely to the surface, as if exhibiting themselves to the greatest advantage. The beautiful little Erycinidæ of South America vary remarkably in their mode of resting. The majority always rest on the under surface of leaves with their wings expanded, so that when they settle they suddenly disappear from sight. Some, however, as the elegant gold-spotted Ilelicopis cupido, rest beneath leaves with closed wings. A few, as the genera Charis and Themone, for example, sit on the upper side of leaves with their wings expanded ; while the gorgeously-coloured Erycinas rest with wings crect and exposed as in the majority of butterflies. The Hesperidæ vary in a somewhat similar manner. All rest on the upper side of leaves or on the ground, but some close their wings, others expand them, and a third group keep the upper pair of wings raised while the hind wings are expanded, a habit found in some of our European species. Many of the Lycænidie, especially the Theclas, have the curious habit, while sitting with their wings crect, of moving the lower pair over each other in opposite directions, giving them the strange appearance of excentrically revolving discs.

The great majority of butterflies disappear at night, resting concealed amid foliage, or on sticks or trunks, or in such places as harmonise with their colours and markings; but the gaily-coloured IIeliconida and Danaida seek no such concealment, but rest at night hanging at the ends of slender twigs or upon fully exposed leaves. Being uncatalle they have no enemies and need no concealment. Day-flying moths of brilliant or conspicuous colours are also comparatively abundant in the tropical forests. Most magnificent of all are the Uranias, whose long-tailed green-and-gold powdered wings resemble those of true swallow-tailed butterflies. Many Agaristidæ of the East are hardly inferior in splendour, while licsts of beautiful clearwings and Ægeriidæ add greatly to the insect beauty of the cquatorial zone.

The wonderful examples afforded by tropical butterflies of the phenomena of sexual and local variation, of protective modifications, and of mimicry, have been fully discussed elsewhere. For the study of the laws of variation in all its forms, these beautiful creatures are unsurpassed by any class of animals; both on account of their great abundance, and the assiduity with which they have been collected and studied. Perhaps no group exhibits the distinctions of species and genera with such precision and distinctness, due, as Mr. Bates

[ocr errors]
« EelmineJätka »