Osmia rufina are black bees with a metallic green luster (Wu 2006). Females have dense yellow to white hair on the gena, thorax, and legs; light orange hair on T1; and T2–T5 are covered with primarily dark brown hair (Wu 2006; Fig 3). Males have white to pale yellow hair on the face, thorax, and abdomen (Wu 2006; Fig 4–6). Female body length is 11–13 mm ,and male body length is 8–9 mm (Wu 2006).
(modified from Wu 2006)
Osmia rufina look similar to O. bicornis and O. pedicornis. Females of these species all have lateral horns and bidentate median apical projection on the clypeus. O. rufina females can be differentiated by the much shorter, rounded median apical projections on the clypeus and the short, triangular-shaped lateral horns on the clypeus. Males are similar in size and hair color and can be difficult to distinguish without dissecting them to see the genitalia and hidden sterna. They can, however, be distinguished by the shape of S8 and the apex of the gonocoxites.
Osmia rufina specimens have been recorded in Beijing, Fujian, and Sichuan in China (Wu 2006).