Source : Webster's Revised Unabridged Dictionary (1913)

Gordius \Gor"di*us\, n. [NL. See {Gordian}, 1.] (Zo["o]l.)
   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.