BUTTERFLY, the common English name of all the diurnal lepidopterous (q.v.) insects, corresponding with the genus papilio, as originally defined by Linnmus, but forming many genera in the most recent entomological systems. Butterflies exhibit a great similarity in almost all respects to other lepidopterous insects, the common charac ters of which will be found in the article on that order; but are distinguished even more than the rest of them generally, by brilliancy of coloring, which in butterflies also belongs to the under as well as the upper side of the wings, whilst the beauty of moths and hawk-moths appears chiefly on the upper side. Accordant with this circumstance, is the further peculiarity, that almost all butterflies, when at rest, usually hold their wings erect, the under side being thus chiefly exhibited; whilst the other lepidopterous insects, when at rest, hold their in a horizontal or somewhat inclined position, and some have them wrapped round the body. Butterflies are also the only lepidopter ens insects which have no spines, bristles, or hooks on the margins of their wings, by which the second wing on each side can be attached to the first, but both when flying and at rest, have all their wings quite separate. The manner in which the scales of the wings are imbricated, gives those of butterflies a smoother appearance than those of moths and hawk-moths. The antennic of butterflies are generally simple, slender, and •elono-ated, and terminated by a little club. Their caterpillars have always sixteen feet (See The pupa Or Chrysalis is angular; is seldom enveloped in a cocoon; is generally suspended by the tail, by means of a silky substance, often to a leaf or twig, but is sometimes supported by bands around the middle; and generally exhibits more or less of that golden coloring from which both the names aurelia (Lat. aurunt) and chrysalis (Gr. chrysos) are derived.
Butterflies are found in all parts of the world; they are to be seen during the sun shine of the brief summer extracting nectar from the flowers even of Greenland and Spitzbergen, but they are most numerous in the warmest regicns; where, however, many of them live chiefly in the shade of moist foliage, in woods and jungles. Dr. Hooker, describing the scenery on the banks of the Great Runjeet in the Sikkin Hima laya, says that " by far the most striking feature consisted in the amazing quantity of .superb butterflies, large tropical swallow-tails, black, with scarlet or yellow eyes on their wings. They were seen everywhere, sailing majestically through the still hot air,
or fluttering from one scorching rock to another, and especially loving to settle on the damp sand of the river edge, where they sat by thousands, with erect wings, balancing themselves with a rocking motion, as their heavy sails inclined them to one side or the •other, resembling a crowded fleet of yachts on a calm day." Butterflies possess no small power of wing; some of them, indeed, of which the wings are comparatively thin and delicate, are inferior in this respect, and have a sort of zigzag flight; but others soar in the air with a steady and continuous motion. Short lived' as they arc all generally believed to be, some of the tropical species perform wonderful migrations; concerning which, however, nothing but the fact is yet well known. " Frequently," says sir James Emerson Tennent in his work on Ceylon, " the •extraordinary sight presents itself of flights of these delicate creatures, generally of a white or pale yellow hue, apparently miles in breadth, and of such prodigious extension .as to occupy hours and even days uninterruptedly in their passage, whence coming no one knows, whither going no one can tell." The number of species of B. is very great, and the arrangement of them has been found difficult, chiefly upon account of the great similarity in all important respects which prevails among them all. They are divided, however, into two well-marked sections, of which the first is characterized by having only a single pair of spurs or spines on the tibia! (or fourth joints of the legs), placed at their lower extremity; whilst in the other section, the tibite of the hinder legs have two pair of spurs, one pair at each extremity. This distinction, seemingly unimportant in itself, is accompanied by other differences. The second section of butterflies may be regarded as forming a sort of eon• netting link between butterflies and hawk-moths. A few British species belong to it, but the species are generally tropical, and sonic of them, found in tropical America, are remarkable for their rapidity and power of flight, and for the migrations which they perform, besides being amongst " the most splendid insects in creation," a resplendent green, inimitable by art, relieving the velvet black of their wings, and varying with every change of light. The beautiful iridescence of the wings of these and many other butterflies is owing to the peculiar position of the scales.