Rhopalum nigrinum KIESENWETTER, 1849; Crabro kiesenwetteri MORAWITZ, 1866
A small, stem nesting solitary wasp. Identification keys are given in Lomholdt (1984) (as R. nigrinum), Richards (1980) and Yeo & Corbet (1995).
Infrequently recorded from a few wetland localities in East Anglia, with very few modern records. Overseas this species is found throughout Europe and eastwards to Japan.