1570s, originally a weasel-like animal in Egypt, Latinized from Greek ikhneumon, literally "searcher, tracker," perhaps because it hunts crocodile eggs, from ikhneuein "hunt for, track," from ikhnos "a track, footstep, trace, clue," of unknown origin. Used by Aristotle for a species of wasp that hunts spiders (a sense in English from 1650s).
any of a large and widely distributed insect group (order Hymenoptera) of considerable economic importance. The name sometimes refers to any member of the superfamily Ichneumonoidea, which includes the families Stephanidae, Braconidae, and Ichneumonidae. The Stephanidae, a largely tropical group, consists of several hundred species, and the Braconidae is a large, widely distributed group found in both temperate and tropical regions