Sphecodes crassus Thomson, 1870

Described as: Sphecodes crassus Thomson, 1870: 100 .

Synonyms: Sphecodes variegatus Hagens, 1874: 40 –41.

Sphecodes divisus Hagens, 1882 (nec Kirby, 1802): 223. Sphecodes valesianus Frey-Gessner, 1903: 100 .

Distribution. Europe north to 64° N, Sweden, Finland and Norway, present on British Isles; Turkey, Iran, and North Africa (Warncke 1992).

Biology. Common species that usually occurs in semi-open biotopes with shrubs, forest-steppes, steppes, and forest margins. In central Europe widespread, although except for warm sites it is never numerous. This species is a nest cleptoparasite of smaller species of Halictidae . Sick et al. (1994) experimentally proved Stoeckhert’s (1933) finding of Lasioglossum pauxillum (Schenck) as a host, Westrich (1989) and Vegter (1993) mentioned also L. punctatissimum (Schenck) as a confirmed host. Other similar species are likely to be hosts as well: L. quadrinotatulum (Schenck) recorded as likely host by Alfken (1912), L. nitidiusculum (Kirby) by Stoeckhert (1933) and L. prasinum (Smith) by Vegter (1993). The hosts can be different in parts of the distributional area, as L. prasinum is rare in central but quite common in north-western Europe.