Osmia (Hapsidosmia)


Family: Megachilidae
Subfamily: Megachilinae
Tribe: Osmiini
Genus: Osmia Panzer, 1806
Subgenus: Hapsidosmia Rightmyer, Griswold, & Brady 2013
Common name: none


Osmia (Hapsidosmia) are dark metallic blue-green bees with black hair throughout their body. They range in body length from 9–14 mm.

Diagnostic characteristics

(modified from Rightmyer et al. 2013)

May be confused with

Female O. (Hapsidosmia) may be confused with female species within O. (Cephalosmia) and O. (Trichinosmia) due to similar mandibular characteristics and the wide cutting edge between the two uppermost teeth. Female O. (Hapsidosmia) can be differentiated from O. (Cephalosmia) and O. (Trichinosmia) by the combination of the triangular process on the lower margin of their mandibles, black scopa, and narrow impunctate margins on their terga (Rightmyer et al. 2013). Male O. (Hapsidosmia) may be confused with male O. (Cephalosmia) and O. (Trichinosmia) because of their thick gonoforceps, sclerotized S4 with short hairs on the disc, and sometimes dense hairs on the apical margin. They can be differentiated by the distinctly concave apical margins of S2 to S5 (Rightmyer et al. 2013).

Host associations

Osmia (Hapsidosmia) are specialists of the plant tribe Fabeae (Fabaceae) (Forrest and Chisholm 2016; Spear et al. 2016).

Nesting behavior

Osmia (Hapsidosmia) nest in above ground cavities in woody materials. Cell partitions are comprised of mud or sand grains and leaf pulp (Cane et al. 2007; Forrest and Chisholm 2016). Brood cells are placed linearly within the cavity. Each cell, which contains a single egg, is provisioned with a mass of pollen and nectar (Forrest and Chisholm 2016).


Osmia (Hapsidosmia) is monotypic with only one described species: O. iridis (Rightmyer et al. 2013).


Osmia (Hapsidosmia) can be found throughout the western U.S., ranging from the Rocky Mountains to California and Oregon (Michener 2007).

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

<p><em>Osmia iridis </em>female face, photo: Chelsey Ritner</p>
Osmia iridis female face, photo: Chelsey Ritner
<p><em>Osmia iridis </em>​female lateral habitus, photo: Chelsey Ritner</p>
Osmia iridis ​female lateral habitus, photo: Chelsey Ritner
<p><em>Osmia iridis </em>​female abdomen, photo: Chelsey Ritner</p>
Osmia iridis ​female abdomen, photo: Chelsey Ritner