Osmia (Hemiosmia)


Family: Megachilidae
Subfamily: Megachilinae
Tribe: Osmiini
Genus: Osmia Panzer, 1806
Subgenus: Hemiosmia Tkalců, 1975
Common name: none


Osmia (Hemiosmia) are non-metallic bees with pale pubescence on their head, thorax, and abdomen, and often have apical fasciae on their terga. They range in body length from 7–13.5 mm (Michener 2007).

Diagnostic characteristics

(modified from Michener 2007)

May be confused with

Female Osmia (Hemiosmia) may be confused with O. (Cephalosmia) because both subgenera can have an angle or tooth on the inner ventral margin, but can be differentiated by the smaller and more closely punctate clypeus (Michener 2007).

Host associations

Osmia (Hemiosmia) are specialists on Fabaceae (Haeseler 2008; Rozen et al. 2010; Müller 2018). Osmia iberica has also been observed collecting from Antirrhineae (Müller 2018).

Nesting behavior

Species within the subgenera O. (Hemiosmia) often use masticated leaves to build cells in nests in excavated burrows in loose soil (Haeseler 2008; Rozen et al. 2010). Osmia balearica nests in burrows in loose, sandy soil near dead plants. The dead plant roots are used to attach the cells in the ground. Similar to O. balearica, O. uncicornis and O. difficilis also nest in excavated burrows in loose, sandy or gravely soil. In O. difficilis, plant roots were not attached to the cell as seen in O. balearica and O. uncicornis (Haeseler 2008; Müller 2018). Osmia argyropyga nest in abandoned nest cells of Megachile pyrenaica (Müller 2018).


Osmia (Hemiosmia) contains seven species (Müller 2018). None are known to occur in the U.S. or Canada.

Known invasives

There are no known invasives.


Osmia (Hemiosmia) can be found from the Mediterranean to East and Central Asia (Michener 2007).

​Distribution map generated by Discover Life -- click on map for details, credits, and terms of use.

<p><em>Osmia balearica</em> male face, photo: Chelsey Ritner</p>
Osmia balearica male face, photo: Chelsey Ritner
<p><em>Osmia balearica</em> male lateral habitus, photo: Chelsey Ritner</p>
Osmia balearica male lateral habitus, photo: Chelsey Ritner
<p><em>Osmia balearica</em> male abdomen, photo: Chelsey Ritner</p>
Osmia balearica male abdomen, photo: Chelsey Ritner