none Studies of over 22000 larvae of (a) R. buoliana and over 36000 of (b) E. dodecella collected in Poland showed that endoparasitism averaged 55.5 and 31% respectively. Some 85 species are listed and morphological and biological data for several species are given. The most effective species were: Orgilus obscurator, Temelucha interruptor, Pristomerus orbitalis, Campoplex [Sinophorus] ramidulus and Sinophorus crassifemur on (a), and P. orbitalis, Macrocentrus buolianae, Copidosoma geniculatum, Campoplex rufinator, Apanteles lemariei and Parasitylenchus sp. Parasitism increased with host density which was highest in 7-12 yr old stands and lowest in stands of 5 yr old and younger. Mortality of (a) and (b) was greatest in May and early June and in stands up to 5 yr old. The main factor limion (b).