Source : Webster's Revised Unabridged Dictionary (1913)

Hemimetabolic \Hem`i*met`a*bol"ic\, a. (Zo["o]l.)
   Having an incomplete metamorphosis, the larv[ae] differing
   from the adults chiefly in laking wings, as in the
   grasshoppers and cockroaches.

Source : WordNet®

hemimetabolic
     adj : (of an insect with aquatic young) undergoing incomplete
           metamorphosis in which the young does not resemble the
           adult [syn: {hemimetabolous}, {hemimetamorphous}, {hemimetamorphic}]