An illustrated key to the cuckoo wasps (Hymenoptera, Chrysididae) of the Nordic and Baltic countries, with description of a new species Author Paukkunen, Juho Author Berg, Alexander Author Soon, Villu Author Odegaard, Frode Author Rosa, Paolo text ZooKeys 2015 548 1 116 http://dx.doi.org/10.3897/zookeys.548.6164 journal article http://dx.doi.org/10.3897/zookeys.548.6164 1313-2970-548-1 D5D7B51E5AC6460D9B3C7584E46F9B3F D5D7B51E5AC6460D9B3C7584E46F9B3F Taxon classification Animalia Hymenoptera Chrysididae Chrysis ruddii Shuckard, 1837 Fig. 96 Chrysis Ruddii Shuckard, 1837: 163. Chrysis auripes Wesmael, 1839: 175. Diagnosis. Length 7-10 mm. As in most other species of the Chrysis ignita group, the head and mesosoma are mainly blue or green and the metasoma is dorsally golden red. However, the mesoscutum, mesoscutellum and propodeum, and often also tegulae and mesopleuron, have extensive golden or coppery reflections in the female. The sternites and legs are ventrally coppery red in both sexes. The punctation of the tergites is very fine and dense throughout, punctures being of uniform size (Fig. 96). In the male, the punctation is often somewhat sparser, and therefore it is more easily confused with other similarly coloured species of the Chrysis ignita group (e.g. Chrysis subcoriacea ). The combination of a short pronotum (length less than one fourth of its width), non-metallic F1 and coppery red sternites should be used to distinguish Chrysis ruddii males reliably from other species of the group. Distribution. Denmark, Estonia, Finland, Latvia, Lithuania, Norway, Sweden. Relatively common. - West Palearctic: Europe, Asia Minor ( Linsenmaier 1997 ). Biology. Habitat: dry meadows, rocky outcrops, cliffs, clay banks, forest margins. Adults occasionally visit flowers of Apiaceae and Euphorbiaceae ( Heinrich 1964 , Linsenmaier 1997 , Rosa 2004 , 2006 ). Flight period: mid-May to early August. Host: primarily Ancistrocerus oviventris (Wesmael) ( Berland and Bernard 1938 , Banaszak 1980 , Morgan 1984 , Kunz 1994 , our own obs.), but possibly also Ancistrocerus parietum (Linnaeus), Ancistrocerus scoticus (Curtis), species of Eumenes Latreille, Odynerus spinipes (Linnaeus) and Odynerus reniformis (Gmelin) ( Vespidae ) (Forsius in Trautmann 1927 , Berland and Bernard 1938 , Banaszak 1980 , Kunz 1994 , Martynova and Fateryga 2015 , our own obs.). Records stating solitary bees (e.g. Hoplitis adunca (Panzer) and Hoplitis anthocopoides (Schenck)) as hosts are doubtful, as bees differ significantly in their biology from the vespid hosts.