Only 2 parasites of the larch sawfly,Pristiphora erichsonii(Hartig), were found in all 16 study plots in northern Minnesota from 1970–72: the tachina flyBessa harveyi(Townsend) averaged 30% parasitism over all plots; and the ichneumonMesoleius tenthredinisMorley seldom exceeded 10% parasitism. Approximately 26% of theB. harveyiadults emerged in late-summer rather than the more beneficial spring emergence.Olesicampe benefactorHinz, an ichneumon introduced into Minnesota in 1971 and 1972, was recovered from all 8 release plots. Parasitism reached 48% in one release plot, but was ca. 2% in other release plots by 1972. Dispersal into Minnesota, from releases in 1961 in Manitoba, was conspicuous by 1972 whenO. benefactorwas recovered from 5 of 8 check plots.Mesochorus dimidiatusHolmgren, an ichneumon hyperparasite ofO. benefactor, was found in Minnesota for the 1st time.