ichneumon: [16] Ichneumon comes from a Greek word which meant literally ‘tracker’. This was ikhneúmōn, a derivative of íkhnos ‘track, footstep’. Aristotle used it as the name for a species of wasp that hunted spiders, and it was adopted into English in this sense for the ichneumon fly, a wasplike insect with parasitic larvae, in the 17th century. Its original English application, however, was to a variety of African mongoose which ‘tracks down’ or hunts out crocodile eggs. [ichneumon etymology, ichneumon origin, 英语词源]