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 Hedychridium zelleri (Dahlbom, 1845) Hedychrum Dahlbom, 1845: 2. Hedychridium zelleri : du Buysson (in Andre ) 1892: 183. Diagnosis. Length 2-4 mm. The species differs from other species of Hedychridium by its smaller size and almost completely green or bluish body, which occasionally has weak golden reflections dorsally on the mesosoma. The tarsi are pale brown. Exceptionally small and greenish males of Hedychridium ardens can resemble Hedychridium zelleri , but they have sparser and coarser punctation dorsally on the mesosoma. Distribution. Finland. Rare. - West Palearctic: northern and central Europe ( Linsenmaier 1959 ). Biology. Habitat: sparsely vegetated sandy areas, usually near seashore. Adults are occasionally found on flowers. Flight period: late June to early August. Host: species of Miscophus Jurine ( Crabronidae ) ( Mueller 1918 , Saure 1998 , our own obs.). In central Europe, possibly also Diodontus tristis (Vander Linden) and Diodontus minutus (Fabricius) ( Jacobs and Kornmilch 2007 ).