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Protosmia rubifloris (Cockerell, 1898)


Scientific Name: Protosmia rubifloris (Cockerell, 1898)

Common Name: Prong-faced Slender-Mason Bee


Chelynia rubifloris Cockerell, 1898: 50 [♀].

     Syntype ♀. USA, Washington, Seattle [14 May 1897], by T. Kincaid [USNM no. 24138].

Chelostoma rubifloris edwardsii Cockerell, 1916: 157 [♀]. Synonymy by Michener (1938: 127).

     Holotype ♀. USA, California, Amador County, by H. Edwards [BMNH no. B.M. Type Hym 17a.1962].

Raphidostoma ceanothi Cockerell, 1936: 134 [♂]. Synonymy by Michener (1938: 127).

     Holotype ♂. USA, California, Redwood Highway, Underwood’s Cabins, by Hooker [CAS no. 4256].

Protosmia ribifloris Nelson, Frost, and Nielson, 2021: 8. Lapsus of Protosmia rubifloris (Cockerell, 1898).


Taxonomic notes: Michener (1938: 127) indicated that the type of Chelynia rubifloris Cockerell, 1898, though no lectotype has been designated from the two syntype specimens.

As noted by Michener (1938: 127), Raphidostoma ceanothi is the male of Protosmia rubifloris, and Chelostoma rubifloris edwardsii Cockerell, 1916 represents the size variation within this species.

Distribution in Canada: Nelson et al. 2021 [AB].

The record of this species from northern Alberta by Nelson et al. (2021: 8) is well out of the expected range of this species in Canada. It is likely that the specimen in question is a misidentified female of Hoplitis robusta (Nylander, 1848), a much more widespread species; when proposing the genus Chelostomopsis Cockerell, 1925, Cockerell (1925: 206) noted that Formicapis Sladen, 1916 (the female) also had a process on the clypeus, though it has a different shape. As such, there are no confirmed records of this species in Canada, though it has been found just south of the border of southcentral British Columbia (Western Interior Basin), so likely occurs in Canada.


Cockerell TDA (1898) New and little-known bees. The Canadian Entomologist 30(3): 50-53.

Cockerell TDA (1916) New and little-known bees. The Entomologist 49: 156-160.

Cockerell TDA (1936) Bees from Northern California. The Pan-Pacific Entomologist 12: 133-164.

Michener CD (1938) The bees of the genera Chelostomopsis, Formicapis, Robertsonella and Prochelostoma (Hymen.: Megachilidae). Entomological News 49(5): 127-132.

Nelson CJ, Frost CM, Nielsen SE (2021) Narrow anthropogenic linear corridors increase the abundance, diversity, and movement of bees in boreal forests. Forest Ecology and Management 489: 119044

Sociality: Solitary
Nesting: Cavity Renter
Pollen Specialization: Narrow Oligolecty
Wintering Stage: Adult

Crop Preference: Not Available
Non Crop Preference: Not Available