TremexTre"mex\, n. [NL.] (Zo["o]l.) 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. Note: The pigeon tremex (Tremex columba), a common American species, infests the elm, pear, and other trees.