Ichneumon wasp

Ichneumon wasp, parasitic wasp (family Ichneumonidae) equipped with a long egg-laying organ, the ovipositor, like a hypodermic needle. It lays its eggs in the larvae of other insects and when its own larvae hatch they feed on the tissues of host or hosts. The host, such as a caterpillar, continues to live with the ichneumon larva inside it until pupation. Then the parasite kills its host and pupates itself. Some species of ichneumon wasps can penetrate 2 in (5 cm) of wood with their ovipositors to lay eggs on the larvae of horntails (large sawflies that are pests in timber plantations). These ichneumon wasps have been specially introduced into plantations to keep down the numbers of horntails.