Osmia nigriventris (Zetterstedt, 1838)

Biology: 

Nest in holes in wood blocks, pine bark, and old stumps. Cell partitions and caps are made of leaf pulp (Cane et al. 2007).

Diagnostic description: 

Females of this species are known by the swollen clypeal margin (approaching the extreme look found in O. bucephala, but unlike in that species, there is no metallic coloration in the integument of the meso- and metasomata). Males are known by the strongly reflexed apicolateral angles of T5 and T6. Unlike in O. bucephala, the midleg tarsal segments 2–4 are not modified or swollen, and S2 is unmodified (S2 of O. bucephala with a low tumescence bordered anteriorly and laterally by several rows of erect bristles).

Distribution: 

In the Nearctic, O. nigriventris is known from Oregon, Idaho, Wyoming, and Michigan north to Yukon and the Northwest Territories, east across Canada to Ontario, Quebec, and Newfoundland. In the Palearctic, O. nigriventris is known from France, Italy, and Slovakia north to Norway, Sweden, and Finland and east to Mongolia, northern China, and through Russia to Far Eastern Siberia.

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith