Abstract:Two kinds of egg parasites Ooencyrtus kuwanae (Howard) and Anastatus japonicus Ashmead of gypsy moth Lymantria dispar, were studied in Beijing area from 1987 to 1988 O. kuwanae and A. japonicus has 4 - 5 and 2 - 3generations per year on gypsy moth eggs respectively. The parasitism varied with the dates of the egg masses collected, from 0.64-0.66% of A. japonicus in the eggs collected in late July to 2.26-4.18% in the eggs collected from middle July to middle August, for instance. The adult of these two egg parasites emerged in a two-year period. The emergence rate of O. kuwanae and A. japonicus were 99.35%, 81.0% and 0.7%, 19.0% in the current year and the next year respectively. For the purpose of the preservation of these two egg parasites,the best time to remove gypsy moth egg masses as a control measure is from late September in the current year to late March of the next year.