ichneumon fly

WordReference Random House Unabridged Dictionary of American English © 2026

ichneu′mon fly′, 

1. Insects any of numerous wasplike insects of the family Ichneumonidae, the larvae of which are parasitic on caterpillars and immature stages of other insects.

Also, ich•neu′mon•fly′. 

• 1705–15

Collins Concise English Dictionary © HarperCollins Publishers::

ichneumon fly, ichneumon wasp noun

1. any hymenopterous insect of the family Ichneumonidae, whose larvae are parasitic in caterpillars and other insect larvae