Coleoptera (Beetles)
Minute to large insects whose fore wings, not used in flight, are modified into horny or leathery elytra which almost always meet to form a straight mid-dorsal suture: hind wings membranous, folded beneath the elytra, or often reduced or wanting. Mouthpar
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COLEOPTERA (BEETLES) Minute to large insects whose fore wings, not used in flight, are modified into horny or leathery e/ytra which almost always meet to form a straight mid-dorsal suture: hind wings membranous, folded beneath the elytra, or often reduced or wanting. Mouthparts adapted for biting: ligula variably lobed. Prothorax large and mobile, mesothorax much reduced. Abdominal tergites often little sc/erotized. Metamorphosis complete: larvae campodeiform or cruciform, seldom apodous, with mandibulate mouthparts: pupae adecticous and exarate, rarely obtect.
The Coleoptera number approximately 330 ooo described species, and are consequently the largest order in the animal kingdom: about 3700 species inhabit the British Isles. Although they are the predominant insects of the present epoch beetles are not seen as frequently as members of other orders because of their more concealed habits. Their adaptability and the structural modifications which they exhibit have evidently contributed much to their dominance, for the adults of no other order of insects have invaded the land, air and water to the same extent. The habits of beetles, therefore, are extremely varied: they are more especially insects of the ground and either inhabit the soil itself, or the various decaying animal and vegetable substances. Dung, carrion, refuse of all kinds, humus, rotting wood and fungi all support large associations of Coleoptera. The members of twelve families are true aquatic insects while many other families have aquatic or semiaquatic representatives. The Chrysomeloids and most Curculionoids are usually met with in association with herbaceous plants, bushes and trees. Representatives of the most diverse families, whether they be aquatic or terrestrial, possess ample hind wings and readily take to flight. Several species are littoral and are daily submerged by the tides. A considerable number of beetles occur in close relation with man since they are found in wool, furs, hides, furniture, museum specimens and in dry stored foods and drugs. The great solidity of the integument in the majority of species has been an important factor in protecting them against enemies of various kinds. The various sclerites are fitted together with a precision that marks them out as truly marvellous pieces of natural mechanism. Included in the order are some of the largest and also some of the most minute of living insects. Among the Scarabaeoids Goliathus regius, Dynastes O. W. Richards et al., Imms’ General Textbook of Entomology © O. W. Richards and R. G. Davies 1977
COLEOPTERA (BEETLES)
hercules and Megasoma elephas attain a body-size not found outside the Coleoptera: D. hercules (including the cephalic horn) measures up to about 155 mm long and the Cerambycid Macrodontia cervicornis (including the mandibles) attains approximately the same dimension. On the other hand, among the Corylophidae and Ptiliidae are insects so minute that they may hardly reach a length of o· 5 mm. The literature on Coleoptera has assumed enormous proportions. For a
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