Identification of the European Species of Batakomacrus (Hymenoptera, Ichneumonidae, Orthocentrinae)

The present paper provides a first illustrated key containing all European species of the genus Batakomacrus Kolarov, 1986. A new combination is established: Orthocentrus ambiguus Holmgren, 1858 is transferred to Batakomacrus and the following synonymy is proposed: B. ambiguus comb. n. = B. sylvicola Humala, 2010 syn. n. Batakomacrus ambiguus is recorded for the first time from Finland, Greece, Italy, Moldova, and Spain; B. caudatus (Holmgren, 1858) from Belgium; B. flaviceps (Gravenhorst, 1829) from Greece; and B. noyesi Broad, 2010 from Norway and Sweden. Males of B. ambiguus comb. n. and B. noyesi are described and illustrated.