Source : Webster's Revised Unabridged Dictionary (1913)

Sawfly \Saw"fly`\, n. (Zo["o]l.)
   Any one of numerous species of hymenopterous insects
   belonging to the family {Tenthredinid[ae]}. The female
   usually has an ovipositor containing a pair of sawlike organs
   with which she makes incisions in the leaves or stems of
   plants in which to lay the eggs. The larv[ae] resemble those
   of Lepidoptera.

Source : WordNet®

sawfly
     n : insect whose female has a saw-like ovipositor for inserting
         eggs into the leaf or stem tissue of a host plant