Renter: Existing cavities. The females nest in existing cavities in dead wood, empty snail shells (e.g. Helix, Zonites) and hollow stems.
Nesting material: The nests are linear, and the cell partitions and closure plug are constructed of leaf mastic (e.g. from Malva). (Banaszak & Romasenko, 1989; Stanisavljević, 2000; Ferton, 1892; S. Werner, personal communication).