Biosystematics of insects living in female birch catkins. V. Chalcidoid ectoparasitoids of the genera Torymus Dalman, Aprostocetus Westwood, Psilonotus Walker and Eupelmus Dalman (Hymenoptera, Chalcidoidea)

Fully grown larvae have been described of chalcidoids belonging to four genera, viz., Torymus Dalman (Torymidae), Aprostocetus Westwood (Eulophidae), Psilonotus Walker (Pteromalidae) and Eupelmus Dalman (Eupelmidae), all parasitoids of gall midges of the genus Semudobia Kieffer (Diptera: Cecidomyiidae), associated with fruit catkins of birch, Betula. Identification keys are provided for mature larvae as well as adults. Phenology and host-parasitoid associations have been analysed from samples collected in The Netherlands at about sea level and from western Germany at an altitude of 760 m. Finally, possible patterns of co-speciation have been discussed for gall midge hosts and parasitoids.