Two new species of Cleruchus (Hymenoptera Mymaridae) from the Netherlands and California, USA, apparently associated with Ciidae (Coleoptera) in bracket fungi

A new species of the fairyfly wasp genus Cleruchus (Hymenoptera: Mymaridae), C. polypori is described and illustrated. The specimens were reared from fruiting bodies of the bracket (polypore) fungus Fomes fomentarius on ca. 150-200 year old Fagus sylvatica trees in The Netherlands. The fungi were infested with the beetles Cis castaneus, C. nitidus and Ennearthron cornutum. (Coleoptera: Ciidae), which are apparent hosts of this newly described taxon. It was also reared from fruiting bodies of the same bracket fungus on Betula sp. in the Netherlands. Females of C. polypori sp. are mostly fully winged, rarely brachypterous or apterous, while males are apterous. Another species from the same group, C. puchus is described from California, USA. The type series of this new species, whose females are fully winged and males are either fully winged or often brachypterous, associated with Polyporus sp., and also from the bracket fungi (Polyporeales: Fomitopsidaceae). New information on the association of Camptoptera aula with the bracket fungi in The Netherlands is also provided