A small animal with six legs and a body in three parts.
A member of a large group of mainly land-dwelling arthropods. The body of the adult is divided into a head, thorax, and abdomen. The head bears a single pair of sensory antennae; the thorax bears three pairs of legs and, in most insects, wings (these are absent in some parasitic groups, such as lice and fleas). Some insects are of medical importance. Various bloodsucking insects transmit tropical diseases, for example the female Anopheles mosquito transmits malaria and the tsetse fly transmits sleeping sickness. The bites of lice can cause intense irritation and, secondarily, bacterial infection. The organisms causing diarrhea and dysentery can be conveyed to food on the bodies of flies.
The common name for any of the class Insecta of the phylum Arthropoda. Insects of medical importance are flies, mosquitoes, lice, fleas, bees, hornets, and wasps. For more information, see entries for individual insects.