gordius

‖n. [ NL. See Gordian, 1. ] (Zool.) A genus of long, slender, nematoid worms, parasitic in insects until near maturity, when they leave the insect, and live in water, in which they deposit their eggs; -- called also hair eel, hairworm, and hair snake, from the absurd, but common and widely diffused, notion that they are metamorphosed horsehairs. [ 1913 Webster ]