Among Melittidae s.str., the genus Macropis is characterized notably by the yellow markings of the male, the two submarginal cells (while the other Melittidae s.str. have three) and the well-developed pygidial plate of both sexes (Michener 1981). The morphological adaptations to collect oil (velvety hairs on the female fore legs) are also characteristic.
Macropis includes 16 species into three subgenera: Macropis s.str., Paramacropis Popov & Guiglia 1936 and Sinomacropis Michener 1981. Each species can be defined by a unique combination of a few features: shape of male yellow facial marking, pilosity of propodeal triangle, punctation of terga, shape of pygidial plate, shape of hidden male sterna and shape of male genitalia (Michener 1981, Wu & Michener 1986, Michez & Patiny 2005).
The genus Macropis is Holarctic. In East-Palaearctic, Paramacropis is distributed Northern the Yellow Sea and Sinomacropis Southern. The subgenus Macropis s.str. is also Holarctic. Three well-distinct species groups can be considered: (i) a West-Palaearctic group (three species) reaching Altai (Russia), Northern Kazakhstan; (ii) an Asian group which includes nine Chinese, East-Siberian and Japanese species; (iii) a Nearctic group with four species mainly distributed along the Eastern coast of the USA and Canada.