The Collaborative International Dictionary of English v.0.48:

Tremex \Tre"mex\, n. [NL.] (Zool.)
   A genus of large hymenopterous insects allied to the
   sawflies. The female lays her eggs in holes which she bores
   in the trunks of trees with her large and long ovipositor,
   and the larva bores in the wood. See Illust. of Horntail.
   [1913 Webster]

   Note: The pigeon tremex (Tremex columba), a common American
         species, infests the elm, pear, and other trees.
         [1913 Webster]