The hosts of Ophion luteus (Linnaeus) (Hymenoptera, Ichneumonidae, Ophioninae) in Europe

A widespread European nocturnal ichneumonid, Ophion luteus, is shown to be a parasitoid of at least two species of noctuid moth, Agrotis exclamationis and A. segetum, probably most frequently a parasitoid of the former. The taxonomy, nomenclature and diagnostic features of this species are discussed. Possible expla nations for a spring-flying generation, usually referred to as the ‘ distans’ morph, are discussed.