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Anthidiellum robertsoni (Cockerell, 1904)


Scientific Name: Anthidiellum robertsoni (Cockerell, 1904)

Common Name: Anthidiellum robertsoni


Dianthidium robertsoni Cockerell, 1904: 4 [♀, ♂].

     Lectotype ♀. USA, California, Rock Creek, by Dr. Davidson [USNM no. 9654].

Anthidiellum robertsoni race citrinellum Cockerell, 1925: 362 [♂]. Synonymy by Michener (1951: 1146).

     Holotype ♂. USA, California, Fresno Co., Huntington Lake at 7000 ft, 17 July 1919, by E.P. Van Duzee [CAS no. 1744].


Taxonomic Notes: Grigarick and Stange (1968: 60) tentatively indicated a type locality of “Rock Creek (?)” California for A. robertsoni Cockerell, though this must be considered the case; although the type specimen at the USNM [no. 9654] does not provide locality details, Cockerell (1914: 92) indicates Rock Creek, not Los Angeles, as a type locality for this species. This mention is considered a lectotype designation, but since Cockerell’s original description indicated three specimens from Rock Creek, but did not give the number of each sex represented, it is only assumed that Cockerell labelled only one specimen with this type no.

Though previous authors have treated A. robertsoni (Cockerell) as a subspecies of A. notatum (Latreille) since Schwarz (1928: 395) indicated that it should be considered a variety of the latter (e.g., Michener 1953: 1046; Grigarick and Stange 1968: 60), based on distinct differences in the cytochrome c oxidase I (COI) gene that resulted in two distinct Barcode Index Numbers (BINs) (see Sheffield et al. 2017), Sheffield and Heron (2019) agreed with Urban (2001: 67) and previous authors (Cockerell 1904: 4, 1925: 362; Swenk 1915: 39; Schwarz 1926: 17; Schwarz 1928: 216; Leech 1948: 39) and considered A. robertsoni a distinct species from the eastern A. notatum (Latreille).

Cockerell’s race citrinellum, described from a single male, appears to be an exceptionally bright yellow form of A. robertsoni; Michener (1951) is here given credit for the synonymy.

DNA Barcode Index Number (BIN): BOLD:AAE5295

Biology: Leech (1948) gave a brief description of a nest of A. robertsoni that was attached to the underside of a piece of Douglas fir in Vernon, BC. Michener (1953) provided illustrations and a brief discussion of larval anatomy. Grigarick and Stange (1968) gave a more general overview of the nesting biology, indicating that females make single-celled nests of resin which are attacvhed to twings or flat pieces of wood. Grigarick and Stange (1968) also indicated that this is a polylectic species, visiting 28 plant genera from 13 families in California.

Distribution in Canada: Criddle et al. 1924 [BC, as Dianthidium notatum Latr.]; Schwarz 1928 [BC]; Buckell 1950 [BC]; Grigarick and Stange 1968 [BC]; Sheffield and Heron 2019 [BC].

Though Schwarz (1928: 216) indicates that he published the first record of this species from Canada, it seems he missed the earlier record of Criddle et al. (1924: 100); it seems that is the same material, based on the collection information (i.e., Summerland, BC, August, by Sladen).


Sheffield CS, Heron JM (2019) The bees of British Columbia (Hymenoptera: Apoidea, Apiformes). Journal of the Entomological Society of British Columbia 115: 44-85.

Swenk MH (1915) Studies of North American bees III. Families Nomadidae and Stelididae. University Studies of the University of Nebraska 15(2): 155-193.

Cockerell TDA (1904) The bees of southern California.—I. Bulletin of the Southern California Academy of Sciences 3: 3-6.

Cockerell TDA (1925) Anthidiine bees in the collection of the California Academy of Sciences. Proceedings of the California Academy of Sciences, Fourth Series 14(15): 345-367.

Leech HB (1948[1947]) Anthidiellum robertsoni and its nest (Hymenoptera: Megachilidae). Proceedings of the Entomological Society of British Columbia 44: 39.

Cockerell TDA (1914) Names applied to the North American bees of the genera Lithurgus, Anthidium, and allies. Proceedings of the United States National Museum 47(2045): 87-94.

Michener CD (1951) Family Megachilidae. In: Muesebeck CF, Krombein KV, Townes HK (Eds) Hymenoptera of America north of Mexico Synoptic Catalog. 2. United States Department of Agriculture Agricultural Monograph, Washington. Pp. 1136-1186.

Grigarick AA, Stange LA (1968) The pollen-collecting bees of the Anthidiini of California (Hymenoptera: Megachilidae). Bulletin of the California Insect Survey 9: 1-113.

Schwarz HF (1928) Bees of the subfamily Anthidiinae, including some new species and varieties, and some new locality records. Journal of the New York Entomological Society 36: 369-418.

Schwarz HF (1926) North American Dianthidium, Anthidiellum, and Paranthidium. American Museum Novitates 226: 1-25.

Schwarz HF (1928) Anthidiinae collected mostly in Canada (Hymenop). The Canadian Entomologist 60(9): 212-217.

Michener CD (1953) Comparative morphological and systematic studies of bee larvae with a key to the families of hymenopterous larvae. University of Kansas Science Bulletin 35(8): 987-1102.

Urban D (2001) Loyolanthidium gen. n. e três espécies novas neotropicais (Hymenoptera, Megachilidae). Revista Brasileira de Zoologia 18(1) : 63-70.

Sheffield CS, Heron J, Gibbs J, Onuferko TM, Oram R, Best L, deSilva N, Dumesh S, Pindar A, Rowe G (2017) Contribution of DNA barcoding to the study of the bees (Hymenoptera: Apoidea) of Canada: progress to date. The Canadian Entomologist 149(6): 736-754.

Sociality: Solitary
Nesting: Mason
Pollen Specialization: Polylectic
Wintering Stage: Mature Larva

Crop Preference: Not Available
Non Crop Preference: Not Available

Distribution: British Columbia
Ecozone: Western Interior Basin

female; lateral view
female; lateral view
male; lateral view
male; lateral view

Distribution Map