Page:Encyclopædia Britannica, Ninth Edition, v. 6.djvu/146

126 second baronet of that name, was born in London. He was educated at home ; and when only fifteen he had made considerable attainments in classical and mathematical studies. From the age of twelve to sixteen he resided in France, and in 1782 was appointed to a writership in India. About a year after his arrival there he was placed in the Board of Accounts in Calcutta ; and three years later he was removed to a situation in the revenue department at Tirhoot, where he pursued his studies in Eastern science and literature. In 1789 he was removed to Purneah, where he investigated the resources of that part of the country, and published his Remarks on the Husbandry and Commerce of Bengal, in which he advocated free trade between Great Britain and India. After eleven years residence in India, Colebrooke began the study of Sans krit ; and to him was confided the translation of the great digest of Hindu law, which had been left unfinished by Sir William Jones. After filling a number of important offices, and publishing some works on Oriental literature, including a Sanskrit grammar and dictionary, he returned to London, where he died, March 18, 1837. He was a director of the Asiatic Society, and many of the most valuable papers in the Society s Transactions were com municated by him.  COLEOPTERA, or, a vast and remarkably homogeneous order of Insects, characterized, as the name implies (*oAeos, a sheath, and Trrepa, wings), by the struc ture of the upper wings, or elytra, as they are called, which are so modified as to form shields for the protection of the under wings the true organs of flight in those insects. The name was given, and the principal characters of the order defined, by Aristotle ; and owing doubtless to their singular and varied forms and habits, the brilliant colouring and great size of numerous species, and that solid consist ence which renders their collection and preservation com paratively easy, Coleopterous insects have since the days of the Stagirite received the special attention of entomologists. The body in Coleoptera is enclosed in a chitinous integu ment of a more or less rigid consistence, and is somewhat oval iu form, although in most cases greatly longer than broad. In this respect, however, the utmost diversity pre vails even among the members of the same family, the form being modified to suit the habits of the insect. Thus, according to Batas, among the South Americau forms of Dermestidce, the species of one group are cubical in shape, and live in dung; those of another, inhabiting the stems of palm trees, are much flatter; those of a third, only found under the bark of trees, are excessively depressed, some species being literally &quot; as thin as a wafer ; &quot; while the members of a fourth group of the same family are cylindri cal in shape, and are woodborers, &quot; looking,&quot; says Bates, &quot; like animated gimlets, their pointed heads being fixed in the wood, while their glossy bodies work rapidly round so as to create little streams of saw-dust from the holes&quot; (Naturalist on the Amazons). The body, in common with that of all other insects, is divided into three parts, head, thorax, and abdomen. The head, which is usually rounded or somewhat triangular in shape (except in the Weevil tribe, where it is produced into an elongated rostrum or snout), bears the organs of the senses. The eyes of beetles are two in number and compound, and in predaceous species are somewhat protuberant, thus affording greater range of vision. The simple eyes, or ocelli, common among butter flies and moths, are almost unknown among beetles, although present in the larvae. In many species, especially oi Lamellicorn Beetles, these organs are more or less com pletely divided by a process known as the canthus ; and in the Gyrinidix, or Whirligigs, the intersection is so complete as to give the appearance of a pair of eyes on each side. In burrowing and cave-dwelling syecies^ ^-hose lives are .spent in almost total darkness, the eyes, although distinctly visible in the young, become more or less atrophied in the adult forms. The two antennae, supposed by some to be organs of hearing, and by others of smell, are placed be tween or in front of the eyes, and usually consist of 11 joints. These differ greatly in form and size, not only in different species, but in the two sexes of the same species, the most prevalent forms being the setaceous, moniliform, serrate, pectinate, clavate, and lamellate. In many groups the antennas are exceedingly short, while in such forms as the Longicorn Beetles they, in a few cases, measure four times the length of the body. The parts which go to form the mouth are typically de veloped in beetles, and for this among other reasons the order Coleoptera has generally been placed at the head of the class of insects. It is known as the masticatory mouth, and consists of the four parts (Plate VI. fig. 1). (1) The labrum, or upper lip, is usually a continuation of the upper surface of the head. (2) The mandibles, or true mastica tory organs, consist of two powerful arched jaws generally dentated, moving horizontally and opposed to each other, the teeth in some cases interlocking, in others, as in the Tiger Beetles, crossing like the blades in a pair of scissors. In many species they are so small as to be almost concealed within the cavity of the mouth, while in such forms as the Stag Beetles they measure half the length of the entire body. The form, and texture of the mandibles are largely depen dent on the nature of the insect s food, being acute and sharply dentated in predaceous species, and thick and blunt in vegetable feeders. Their margins are soft and flexible in those which feed on decaying animal and vegetable matters, while the entire mandibles are soft and flattened in those which live on fluids. (3) The maxillce, or lesser jaws, placed beneath the mandibles, and like them moving horizontally, serve to hold the food and guide it to the mouth. Their extremities are in many cases furnished with a movable claw, and their inner surfaces with a series of bristles, which are probably of use in straining the juices from their food. The maxillae are provided with a pair of appendages called maxillary palps delicate organs that vibrate intensely, and are supposed to be principal organs of touch. (4) The labium, or lower lip, also provided with palps. The thorax bears the organs of locomotion, consisting of three pairs of legs and two pairs of wings (Plate VI. fig. 2). The legs vary in their structure and development accord ing to the habits of the species ; thus in running and walking beetles these organs are usually of equal length, and generally similar in other respects, the anterior pair, however, being often stronger in the male than in the female; and in a few species, as the Harlequin Beetle, the anterior legs are enormously elongated and propor tionately thickened. In burrowing beetles the anterior legs are developed into fossorial organs with broad and strongly dentated tarsi, and in arboreal forms the under side of the tarsi is usually covered with hair, forming a cushion-like sole terminating in toothed claws, by which they are enabled to keep their footing on the leaves and branches of trees. Water beetles generally have the posterior pair of legs elongated, flattened, and ciliated, so as to form swimming organs ; those known as Whirligigs using the middle and posterior pairs for this purpose, while the anterior limbs are employed as rudders ; and jumping beetles, as Haltiddae, have the thighs of the posterior pair of legs greatly thickened for saltatory purposes (Plate VIII. fig. 10). The two anterior wings become solidified in beetles, and are thus rendered useless as organs of flight. They are termed elytra (ZXvrpov, a shield), and serve to protect the delicate wings beneath, I as well as the stiymata, or breathing pores v 