The Embolemidae is a small family with 10-15 species worldwide. E. ruddii is the only species in Britain. Notes on identification may be found in Perkins (1976).

One of our largest pompilids, and until recently, regarded as one of our rarest.

A medium-sized black pompilid. Most records of this species are old, suggesting a decline, or perhaps just elusiveness on the part of the wasp.

This is the larger of the two species of British mutillids (the other being Smicromyrme rufipes). Unlike many aculeate wasps, the female is apterous, a feature which gives it an ant-like appearance, and leads to its being called a 'velvet ant'. The male, however, is fully winged and capable of sustained flight.

See Odynerus spinipes for literature on this species.