Subgenus Osmia (Erythrosmia) Schmiedeknecht, 1885

Morphological diagnosis

Osmia (Erythrosmia) species are nonmetallic, robust and small to medium-sized bees (5.5–8 mm) with short-linear parapsidal lines, a medially keeled to weakly spined metanotum, which, however, is often not evident in O. sparsipuncta Alfken and smaller individuals of the other species, a dull basal area of the propodeum and almost lacking to weak whitish tergal hair bands. Except for O. (Allosmia) rutila Erichson, O. (Hoplosmia) fallax Pérez and O. (Neosmia) rufigastra Lepeletier, they are the only Palaearctic representatives of the genus Osmia with a partly or completely red metasoma (Fig. 24). The females are further characterized by a pollen-harvesting comb of apically twistes bristles on clypeus and frons (Fig. 25, 26) and a whitish metasomal scopa.Additional characters of the males are a rather small tergum 7, whose apical margin is truncated, emarginate or weakly four-lobed (Fig. 30–33), and a pair of broad depressions at the base of sternum 6. As in most males of Osmia, tergum 6 is devoid of a lateral tooth, sternum 2 is enlarged, sternum 3 is medially both emarginate and fringed and sternum 6 lacks membraneous basal flaps.