Source : Webster's Revised Unabridged Dictionary (1913)

Webform \Web"form`\, n. (Zo["o]l.)
   Any one of various species of moths whose gregarious larv[ae]
   eat the leaves of trees, and construct a large web to which
   they retreat when not feeding.

   Note: The most destructive webworms belong to the family
         {Bombycid[ae]}, as the fall webworm ({Hyphantria
         textor}), which feeds on various fruit and forest
         trees, and the common tent caterpillar, which feeds on
         various fruit trees (see {Tent caterpillar}, under
         {Tent}.) The grapevine webworm is the larva of a
         geometrid moth (see {Vine inchworm}, under {Vine}).