Renter: Existing cavities. insect burrows in dead wood and drilled borings in wooden blocks; hollow stems (e.g. Rubus, Sambucus) and drilled borings in pithy stems; cavities within abandoned galls of Andricus kollari with 10-24 cells and of Cynips argentea with 10-12 cells. It is unclear whether the females are able to gnaw burrows of their own in the pith of stems or galls. In galls, pith is sometimes removed to accomodate the cells, which are irregularly arranged within the cavity of the galls.
Nesting material: Cell partitions are made of chewed leaves. The nest plug consists of three to four partitions of leaf pulp separated by 0.5-1mm from each other. When nesting in pithy stems, pith is sometimes incorporated into the leaf matrix of partitions and plug. In the subspecies lapidistructor, the cell partitions are built of small pebbles cemented together with leaf pulp. (Banaszak and Romasenko, 2001; Benoist, 1931; Ducke, 1900; Enslin, 1925, 1933; Ferton, 1920; Friese, 1911b, 1923; Latreille, 1811; Westrich, 1989)