Five exotic parasite species of the European corn borer,Ostrinia nubilalis(Hbn.), were introduced into Nebraska in 1948–1950. Only 3 species became established: a tachinid,Lydella thompsoniHerting (=grissescensRobineau-Desvoidy of Authors); an ichneumonid,Eriborus terebrans(Gravenhorst) (=Horogenes punctorius(Roman)); and a eulophid,Sympiesis viridula(Thomson) (=Eulophus viridulus). Population trends forL. thompsoniandE. terebransare reported for 2 counties for the years 1957–1971. No evidence has been found ofL. thompsonisince 1965 butE. terebranswas widespread and present in low numbers in 1975 and 1976.