Gallfly

noun

1. Any of various small insects, such as a gall midge, a gall wasp, or certain flies in the family Tephritidae, whose larvae cause the formation of galls in plants.
2. An insect which occasions galls on plants by puncturing them; especially, a hymenopter of the group Gallicolæ or Diplolepariæ, as a cynipid. See gall, and cut under Cynips.
3. An insect that deposits its eggs in plants, and occasions galls, esp. any small hymenopteran of the genus Cynips and allied genera. See Illust. of gall.
4. Any of various flies which produce galls.
5. small solitary wasp that produces galls on oaks and other plants