Osmia (Euthosmia)


Family: Megachilidae
Subfamily: Megachilinae
Tribe: Osmiini
Genus: Osmia Panzer, 1806
Subgenus: Euthosmia Sinha, 1958
Common name: none


Osmia (Euthosmia) are slender, blue-green bees with white hairs (Michener 2007). They range in body length from 5–7 mm.

Diagnostic characteristics

(modified from Michener 2007, unless otherwise stated)

  • Gena narrower than the eye in profile.
  • Hind coxa without strong longitudinal carina along inner ventral angle.
  • Malar space shorter than width of the scape.
  • Median flagellar segments are nearly 2 times as long as they are broad.
  • Female clypeus truncation thin, without tufts or brushes of hair beneath margin.
  • Female hypostomal area impunctate and shining, with a single row of long, curled hairs along the lateral margin (Rust and Clement 1972).
  • Female mandible is robust and three-toothed.
  • Male T6 apical margin is evenly convex.
  • Male S2 is not enlarged.
  • Male S2, S3, and S4 are transverse.

May be confused with

Osmia (Euthosmia) may be confused with O. (Melanosmia) due to a lack of enlarged S2 and transverse S2, S3, and S4. However, they can be differentiated by the above diagnostic characteristics (Michener 2007).

Host associations

Analysis of pollen found in O. (Euthosmia) glauca nests shows that they collect pollen from Collinsia spp., and are suspected to be specialists on this genus (Rust and Clement 1972).

Nesting behavior

Osmia (Euthosmia) construct nest cells out of mud in hollow stems and abandoned Sceliphron nests. Nest cells are made in clusters or in linear arrangements depending on the cavity used (Rust and Clement 1972).


Osmia (Euthosmia) contains one species, O. glauca (Michener 2007).


Osmia (Euthosmia) can be found in the U.S. west of the Rocky Mountains, primarily in California (Michener 2007; GBIF 2019).

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

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