Source : Webster's Revised Unabridged Dictionary (1913)

Cecidomyia \Cec`i*do*my"i*a\, n. [Nl., fr. Gr. khki`s, ?, a gall
   nut + myi^a a fly.] (Zo["o]l.)
   A genus of small dipterous files, including several very
   injurious species, as the Hessian fly. See {Hessian fly}.