The sparkles of incident sunlight reflected by the armour of this small and fast female Omalus biaccinctus  (det. Milo van Loon) made it easy to detect on the Salvia plants on which she was hunting. A new garden species!
This rare wasp has several species from the genus Passaloecus as host, among which the garden resident P. gracillis . She does not parasitise the wasp larvae but the aphids that are collected by their host for their offspring .
References1 Nederlands Soortenregister
2 PAUKKUNEN, Juho, et al. An illustrated key to the cuckoo wasps (Hymenoptera, Chrysididae) of the Nordic and Baltic countries, with description of a new species. ZooKeys, 2015, 548: 1.