Length 5–7 mm.
Together with H. roseum this species is easily differentiated from other species of the genus by its non-metallic red or orange metasoma. The head and mesosoma are mainly green or blue, but as opposed to H. roseum, the vertex, pronotum and lateral fields of the mesoscutum have coppery red colour or reflections. This coppery colour is sometimes only weakly visible. The metasoma often has weak purple reflections posteriorly. Especially in the males, the punctation of T3 and T2 is usually coarser compared to H. roseum.
Estonia, Finland, Latvia, Lithuania, Sweden. Rare.
West Palearctic: Europe and western Asia (Linsenmaier 1997).
Habitat: sparsely vegetated sandy areas, dry meadows. Adults visit flowers of Apiaceae (Kusdas and Turner 1955).
Flight period: mid-June to late August.
Host: Astata minor (Kohl) (Crabronidae) (Linsenmaier 1968, Saure 1998, our own obs.).
H. caputaureum was recently considered to be a central and northern European subspecies of H. chloropygum (Arens 2010). However, as these taxa are both well characterised and have partially overlapping distribution areas, we treat them as separate species following Paukkunen et al. (2014).