Illustrated key to the European genera of Opiinae (Hymenoptera, Braconidae), with the description of two new Palaearctic genera and two new species.

An illustrated key to the European genera of the subfamily Opiinae (Hymenoptera, Braconidae) is presented and two new genera are described and illustrated: Cavopius gen. nov. (type species: Opius (Agnopius) daghoides Zaykov & Fischer, 1983) from West and East Palaearctic regions and Pseudosteres gen. nov. (type species: Biosteresadanaensis Fischer & Beyarslan, 2005) from West Palaearctic region. Two new species are described and illustrated: Cephaloplitesgijswijti sp. nov. from Greece and Cavopiusdepressorius sp. nov. from S. Korea. Opius (Hypocynodus) kilisanus Fischer & Beyarslan, 2005 is a new synonym of Cephaloplitesmocsaryi Szépligeti, 1897. The following new combinations are proposed: Cavopiusdaghestanicus (Telenga, 1950), comb. nov. , C.daghoides (Zaykov & Fischer, 1983), comb. nov. , Pseudosteresadanaensis (Fischer & Beyarslan, 2005), comb. nov. , P.arenaceus (Jakimavičius, 1986), comb. nov. , P.christenseni (Papp, 1982), comb. nov. , P.pseudarenaceus (Fischer & Beyarslan, 2005), comb. nov. , and P.riphaeus (Tobias, 1986), comb. nov. Keys to species are provided for Cavopius gen. nov. , Cephaloplites Szépligeti, 1897, and Pseudosteres gen. nov.