Renter: Existing cavities: insect burrows in dead wood and drilled borings in wooden blocks; hollow stems (e.g. Arundo); insect burrows in the soil (e.g. of Anthophora). Nesting material: Cell partitions and nest plug are made of mud. In larger cavities, cells are irregularly arranged with cell walls partially or entirely built of mud. (Beiko, 1987; Nurse, 1904; Ponomareva, 1958)