none. 15 species of parasitoids families Eulophidae, Braconidae and Ichneumonidae have been reared from mines within larvae and pupae of Lithocolletis populifoliella collected in different districts of Moscow (Russian SFSR, USSR), Elachertus inunctus, Pediobius? alcaeus (Eulophidae), Scambus? signatus and Itoplectis? alternans (Ichneumonidae) have been registered as parasitoids of L. populifoliella for the first time. Chrysocharis sp., Sympiesis gordius, Phigalio sp. and Apanteles circumscriptus have been met more often. The different strategies of searching behaviour of parasitoids depending on the abundance of host mines and spatial distribution of leaves are under discussion. The level of parasitism in the outlying districts of Moscow is 20-fold higher than in centre. The causes of this differences are being analysed. (Other species mentioned are A. bicolor, Sympiesis acalle, S. sericeicornis, Cirrospillus elegantissimus, C. vittatus, C. pictus and Mesochorus sp.)