ichneumon fly

noun
1.
any of numerous wasplike insects of the family Ichneumonidae, the larvae of which are parasitic on caterpillars and immature stages of other insects.
Also, ichneumonfly.
Origin
1705-15
British Dictionary definitions for ichneumon fly

ichneumon fly

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