Ichneumon

(invertebrate zoology) The common name for members of the family Ichneumonidae.

The common name for medium- to large-sized insects (wasps) comprising 25,000 species and belonging to the family Ichneumonidae (Hymenoptera); together with the Braconidae (with an additional 15,000 species) they form the superfamily Ichneumonoidea. The majority of ichneumons are slender wasps with long filiform antennae, freely rotating head, and permanantly extruded ovipositor. The ichneumons, found worldwide, are most abundant in heavy vegetational areas such as the edges of woodlands, hedgerows, and in secondary growth vegetation, and are often seen in the woodland canopy or in the litter of the forest floor. Ichneumons are more commonly seen in the spring and fall, as these wasps avoid hot, dry weather. See also Hymenoptera; Insecta.

All members of the family Ichneumonidae are parasitic during their immature stages. They attack a wide variety of insects, usually the larval stages of beetles, butterflies, moths, flies, and other Hymenoptera. Since many of their insect hosts are considered pests of forest and agricultural crops, ichneumons are beneficial and important in biological control. See also Entomology, economic.