none Predation and parasitism of immatures of the bronze birch borer, A. anxius Gory, in European white birch in Pennsylvania were studied. Egg parasitism was 7%, and was due primarily to two encyrtids, Ooencyrtus sp. and Avetianella sp. Five species of larval parasites were recovered. Tetrastichus sp. (Eulophidae), the most common parasite, and Eurytoma sp. (Eurytomidae) were new records from A. anxius, Phasgonophora sulcata Westwood (Chalcididae), Atanycolus charus (Riley) (Braconidae), and an undetermined ichneumonid were less common. Larval parasitism by all species amounted to 18%. Predation by woodpeckers reduced the overwintering larval population by 60%.