Renter: Existing cavities. The females nest in various existing cavities such as insect burrows in dead wood, dead hollow plant stems (e.g. Phragmites) or cavities in the soil (Popovici-Baznosanu 1909; Banaszak & Romasenko 2001; A. Müller unpublished data), possibly also in abandoned nests of aculeates in loess scarps (H. Wiesbauer
personal communication). Occasionally, the ground. The nests contain 1–11 brood cells which are arranged in a linear fashion (all cited in Müller, 2018)
Nesting material: The cell partitions and entrance plug are constructed of minute particles of soil or sand, glued with saliva. (Banaszak & Romasenko,1989). In Phragmites stems, the entire brood cells including their walls may be constructed from mud. The nest is sealed by a single-layered wall of mud at its entrance. The space between the outermost cell and the nest plug is 1.5–5 cm long and usually empty, but is occasionally divided up by an additional wall of mud (Müller, 2018).