The Collaborative International Dictionary of English v.0.48:

Hemimetabola \Hem`i*me*tab"o*la\, n. pl. [NL. See Hemi-, and
   Metabola.] (Zool.)
   Those insects which have an incomplete metamorphosis.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Hemimetabola
    n 1: subclass of insects characterized by gradual and usually
         incomplete metamorphosis [syn: Exopterygota, subclass
         Exopterygota, Hemimetabola]