This is one of the larger Lasioglossum, averaging a little smaller than Lasioglossum calceatum (7-10mm). Identification is tricky, but there are subtle differences when compared to the similar L. calceatum, such as a more oval-shaped head and grey-bloomed tergites. The males of both species are rather small and also quite alike. Both species are primarily black (with a variable amount of red colouration on the abdomen), but the current species has yellow mandibles rather than black. It is one of the commonest Lasioglossum species in Ireland but as a result of its small size it is likely overlooked.

Distribution in Ireland: Widespread throughout and fairly common.

Flight period: Females can be seen from late March-late September. Males fly between June – August.

Habitat: A wide range of habitats are used including unimproved grassland, woodland edges, farmland, heath, parks and gardens. It is generally more frequent in upland areas and sites over acidic soils when compared to L. calceatum. 

Flowers visited: Dandelions, hawkweeds, geraniums, thistles, scabious, buttercups, Yarrow and others. Females are widely polylectic.

Personal records: I have observed this species in the Hillsborough area (Co. Down). It appears to be commoner in the Lagan Meadows and Slievenacloy, both in Co. Antrim. I have also seen it at the Skerries Ballast Pit (Co. Dublin), Furnish Island (Co. Galway) as well as other sites across Ireland. It nests in a variety of settings, such as clay banks, solidified sandy soils and exposed peat hags, sometimes in dense aggregations. It serves as a host for the blood bee Sphecodes monilicornis and possibly Sphecodes ephippius.