Definitions for gall midge
Random House Webster's College Dictionary
any midge of the family Cecidomyiidae, the larvae of which form characteristic galls on plants.
Origin of gall midge:
gall midge, gallfly, gall gnat(noun)
fragile mosquito-like flies that produce galls on plants
Any insect of the Cecidomyiidae family, whose larvae damage crops and other plants, creating galls on the stems and other fleshy parts.