Source : Webster's Revised Unabridged Dictionary (1913)

Eggar \Eg"gar\, n. [Etymol. uncertain.] (Zo["o]l.)
   Any bombycid moth of the genera {Eriogaster} and
   {Lasiocampa}; as, the oak eggar ({L. roboris}) of Europe.

Source : WordNet®

eggar
     n : moth having nonfunctional mouthparts as adults; larvae feed
         on tree foliage and spin egg-shaped cocoons [syn: {egger}]