Coleoptera

Coleoptera. The order of Insects including those forms in which the anterior wings are hardened into a pair of horny sheaths, which protect the soft hinder flying wings; the former are known as the elytra. The Coleoptera is numerically by far the largest of the orders of Insects, and includes more than 100,000 species. These are generally known as beetles; but this name is very loosely applied, including many forms, such as the Black beetles, which are not true Coleoptera, and excluding many groups, such as the Turnip Fleas, which really belong here. Among other characters that separate the Coleoptera from the other orders of Insects, in addition to their wings, are the following: (1) The mouth parts are adapted for biting instead of sucking; (2) and the metamorphosis is complete, i.e. between the adult flying stage and the larval grub stage there intervenes a period of rest, during which the insect is enclosed in a pupa. These three stages correspond to the caterpillar, chrysalis, and butterfly stages of the butterflies and moths. These characters enable us to assign to the Coleoptera certain insects which have lost their wings, or in which these are rudimentary, often being concealed beneath the two elytra, which have fused together. For an account of the anatomy of a type of this order see Stag-Beetle. The Coleoptera have a very varied mode of life. Many are aquatic, such as the Whirligig Beetles (Gyrinidae) and Dytiscus; the larvae of the latter are known as "fresh-water shrimps." Others are parasitic; and others, like the Cockchafers, at least in the larval stage, live on the roots of plants, to which they may do serious damage. A large number lay their eggs in dung, and upon this the larvae feed. In the Weevils the eggs are placed in the kernel of a nut, through the shell of which the grubs bore their way at the end of larval life. The Bacon Beetles (Dermestus) lay their eggs in bacon, in which the larvae live. The largest of the British species is the Stag-Beetle.