A very bright, black and yellow cuckoo bee and one of the largest of our Nomada species. In common with its hosts (Andrena species of the nigroaenea-group) this is a very widespread and frequently found species, often seen flying over short vegetation and bare ground in sunny places during the spring and, in smaller numbers, late summer. These later dates support the supposition that its hosts may also have a later flight period than has been previously recognised.

An identification key is available (Else, 1999). Females from the British mainland and the Isle of Man have black scopal hairs on the fifth and sixth sterna, those occurring in Ireland have the sternum with the entire scopa reddish-golden.

An identification key is available (Else, 1999). Females from the British mainland have the scopal hairs on sterna 5-6 black. Those from the Isle of Man and from Ireland have them extensively golden red, although the black form has been seen in Ireland too (D B Baker, pers. comm.).

One of a suite of eight superficially similar species. All are medium-sized to large solitary bees nesting in holes, largely in various forms of timber either in standing deadwood or fence posts.

Extinct in Britain. A single record from 1847. Else (1999) includes this species in the notes but not the key, although it should be included in his forthcoming monograph. A key is provided in Amiet et al. (2004).

A key is available in Perkins (1925). Else & Edwards (in press) will also have a key. Formerly included in Chalicodoma, now treated as a subgenus of Megachile.

An identification key is in Else (1999).

A very similar species to the more common Lasioglossum lativentre (Schenck) and some records are probably due to misidentification of that species. Perkins (1922) unfortunately transposed the male genitalia characters, the most reliable way of distinguishing the two species, in his seminal paper on Lasioglossum.