Reference

Alexander Gutbier (1915): On the biology of some solitary bees; on the classification and evolution of nests of bees and wasps (Hymenoptera: Aculeata). [A continuation]. [Ru; 1 photo, 9 figs. Date: [30].IX.19153...]. – Lyubityel' Prirody (Petrograd) – 1915 (9): 257 - 275.