onion fly
nounDefinition of onion fly
1
: a dipterous insect of the family Anthomyiidae whose larva feeds on onion bulbs
especially
: an originally European insect (Hylemya antiqua) now widely distributed in America
2
: an insect (Tritoxa flexa) of the family Otitidae with habits like those of the onion fly
— called also black onion fly