Genus: Osmia Panzer, 1806
Subgenus: Cephalosmia Sladen, 1916
Common name: none
(modified from Michener 2007, unless otherwise stated)
Female O. (Cephalosmia) may be confused with female O. (Hemiosmia) because of the angle or tooth on the inner ventral margin, but can be differentiated by the large, dispersed punctures or the complete lack of punctures on the clypeus (Michener 2007).
Osmia (Cephalosmia) have been observed visiting Asteraceae, and three species are known specialists (Cane 2016).
Osmia (Cephalosmia) typically nest in abandoned beetle burrows in wood (Michener 2007). Cell partitions are constructed out of macerated leaf materials and sometimes mud (Michener 2007). The egg is placed inside a small pocket within the center of the pollen store; this is an unusual characteristic, as most eggs are placed in a cell on top of a food mass (Rust 1974).
Osmia (Cephalosmia) contains five species (Michener 2007).
Osmia (Cephalosmia) can be found in western North America, ranging from the Northwest Territories of Canada to Baja California, Mexico. They are rarely found east of the Great Lakes (Michener 2007).