centipede

CE5

Centipede, representative of the class Chilopoda

centipede, common name for members of a single class, Chilopoda, of the phylum Arthropoda. Centipedes are the most familiar of the myriapodous arthropods, which consist of five groups of arthropods that had a separate origin from other arthropods. Centipedes are widely distributed in temperate and tropical lands, living in the soil or surface litter, and under logs or rocks. The largest species, Scolopendra gigantea, may reach 12 in. (30 cm) in length; many other tropical species are over 6 in. (15 cm) long. Temperate species are usually only about 1 in. (2.5 cm) long. The flattened body is divided into a head and a trunk composed of segments, or somites. The head bears long antennae, jaws, and two pairs of maxillae used for food-handling. Although the name centipede means “hundred-legged,” the average is actually about 35 pairs of legs, one pair on each body segment except for the last two, the pregenital and genital segments. The appendages of the trunk's first segment are modified into claws that are equipped with poison glands and are used to kill or stun prey. Larger centipedes can cause a painful bite, but the poison is not powerful enough to cause death in humans. Centipedes are chiefly nocturnal and predominantly carnivorous, feeding on insects or other small arthropods, though the largest species can kill small vertebrates. Sexes are separate, and some species have extensive courtship ceremonies. Members of the orders Lithobiomorpha and Scutigeromorpha have 15 pairs of legs as adults. These centipedes release eggs singly in the soil. Not all of the body segments are present at the time of hatching, and the young add somites and pairs of legs as they molt. Lithobiomorphs are widely distributed in temperate and subtropical regions. The swift scutigeromorphs have very long legs; the last pair is often extended to the rear, serving as posterior tactile appendages. Although especially abundant in the tropics, they include Scutigera forceps, the rather common house centipede of temperate climates. The house centipede has long, delicate legs and compound eyes. It feeds on roaches, clothes moths, and other insects. Members of the orders Geophilomorpha and Scolopendromorpha produce clusters of eggs, which are guarded while they develop. A full set of body segments and legs is present at hatching. Geophilomorphs have very long, slender bodies with from 31 to over 180 pairs of short legs. They are burrowing forms and are found in the soil from temperate to tropical regions. The scolopendromorphs are also widely distributed, but are more abundant in the tropics. They have from 21 to 23 pairs of legs and include the largest and most colorful centipede species.

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