Table 2.

Differentiating characters of male Osmia svenssoni, Osmia steinmanni, and Osmia aquilonaria.

	Osmia svenssoni	Osmia steinmanni	Osmia aquilonaria
gonoforceps	Fig. 69; apically evenly tapering, short; preapically with outer margin widened, broader than basally; basally swollen in lateral view; hairs on preapical angle mostly on dorsal surface, relatively sparse	Fig. 66; preapically not widened, about as broad as basally; not swollen in ventral or lateral view; hairs on preapical angle mostly on dorsal surface, moderately dense	Fig. 26; apically long and slender, preapically not swollen in ventral view; basally swollen in lateral view; hairs on preapical angle mostly on lateral surface, relatively dense
S4	Fig. 70; narrower gap between brushes of hairs; brushes of hairs densely setose	Fig. 67; wider gap between brushes of hairs; brushes of hairs sparser	Figs 24, 25; wider gap between brushes of hairs, brushes of hairs densely setose
propodeal triangle	entirely granulose	lower two-thirds shining	Fig. 21; entirely granulose
head	quadrate in outline	round in outline	Fig. 20; semi-quadrate in outline
hind basitarsal segment, tooth placement (measured along length, from apical margin to basal margin)	one-fourth to one-fifth from apical margin	one-third from apical margin	Fig. 22; one-third to one-fourth from apical margin (shorter and broader than in Osmia svenssoni)