Excavator: Ground. Nest burrows have been found both singly, on a hard path in Surrey (Guichard, 1972), or as small aggregations of about a dozen burrows on sandy paths in Hampshire (I. Hudson, pers. comm.) and West Sussex (M. Archer and M. Edwards, pers. comm.).
In Germany aggregations of up to one hundred nests are known (Westrich, 1989). According to Malyshev (1926, 1936) the nest entrances are left open during the provisioning period, but are closed during the mid-day hours. Brood cells lie 5-10 cm deep; their walls are provided with small droplets (nectar?). Nest described by Malyshev (1926). A nest entrance and an opened, provisioned cell are illustrated by Westrich (1989).