Source : Webster's Revised Unabridged Dictionary (1913)

Ametabolic \A*met`a*bol"ic\, Ametabolous \Am`e*tab"o*lous\, a.
   (Zo["o]l.)
   Not undergoing any metamorphosis; as, ametabolic insects.

Source : WordNet®

ametabolous
     adj : undergoing slight or no metamorphosis [syn: {ametabolic}]
           [ant: {metabolic}]