FIGURES 1–5: Osmia (Allosmia). 1: Female of O. melanura at the entrance of her nest. 2: Female of O. rufohirta rolling her nest towards a protected place. 3: Female of O. sybarita rolling her nest into a self-excavated hole in sandy soil (photo N. Vereecken). 4: Opened nest of O. melanura with one brood cell and a nest plug at the shell opening composed of a one-layered partition of leaf pulp followed by broken pieces of gastropod shells embedded into a matrix of leaf pulp. 5: Opened nest of O. rufohirta with one brood cell and a nest plug at considerable distance from the shell opening consisting of a central layer of earth crumbs sandwiched between two partitions of leaf pulp (photo P. Westrich).