29. Hedychridium caputaureum Trautmann & Trautmann, 1919

Hedychridium roseum var. caputaureum Trautmann & Trautmann 1919: 35. Holotype ♀; Germany: Bronnamberg (ZMB) (examined).

Hedychridium chloropygum spatium Linsenmaier, 1959: 59. Holotype ♂; Hungary: Simontornya (NMLS). Linsenmaier 1987: 142, Rosa & Soon 2012.

Hedychridium mediocrum [nec Linsenmaier, 1987]: Cederberg 2000: 177, Cederberg 2005: 290, Soon 2004: 45, Sörensson 2008e.

Hedychridium caputaureum: Cederberg 2005: 290, Franzén & Norén 2009: 40.

Hedychridium chloropygum [nec Buysson, 1888]: Sörensson 2008c, Cederberg et al. 2010: 353, Orlovskytė et al. 2010: 146, Paukkunen 2010: 540, Ivarsson 2011: 13, Molander 2011: 95, Ranta 2012: 33, Dyntaxa 2013, Johansson, in press.

Hedychridium chloropygum caputaureum: Arens 2010: 445.

Material examined. *Russian Fennoscandia: Ik: Metsäpirtti [= Zaporozhskoe], [1930s], 1 ♀ (P. Niemelä); Rautu [= Sosnovo], [1921], 1 ♀ (R. Forsius); Sakkola [= Gromovo], 11.VII.1934, 2 ♀♀ (A. Merisuo); Terijoki [= Zelenogorsk], 9.VII.1932, 1 ♀, and [1930s], 1 ♀ (V. Löfgrén); Uusikirkko [= Polyany], [1930s], 2 ♀♀ (P. Niemelä).

Distribution. Estonia, Finland, Latvia, Lithuania, Sweden, *Russian Fennoscandia.—Westpalearctic: Europe and western Asia (Linsenmaier 1997).

Remarks. Hedychridium caputaureum has often been confused with H. roseum in the Nordic and Baltic countries and its distribution is still not well known. It has possibly been overlooked in Denmark and Norway. Compared to H. roseum, it is less common and strictly confined to areas with populations of its crabronid host Astata minor. It has been classified as vulnerable in Finland (Paukkunen 2010) and Sweden (Cederberg et al. 2010).

Arens (2010) considered caputaureum to be a subspecies of H. chloropygum, while Linsenmaier (1959) had earlier classified it as a subspecies of H. roseum. According to Arens, H. chloropygum consists of two subspecies in Europe: ssp. chloropygum (distributed from the Iberian peninsula to Hungary) and ssp. caputaureum (from central, southeastern and northern Europe). A third subspecies, ssp. ottomanum, is found in Asia Minor. The taxa spatium and densum of Linsenmaier (1959) were synonymized with ssp. caputaureum by Arens. We consider chloropygum and caputaureum to be separate species, as they are both well characterized and have partially overlapping distribution areas. Also e.g. Niehuis (2001) and Rosa (2006) treated H. caputaureum as a distinct species.