Hoplitis albifrons argentifrons (Cresson, 1864)

Monumetha argentifrons Cresson, 1864: 387 [♂]. Synonymy by Michener (1947a: 185), as a subspecies of Hoplitis albifrons (Kirby, 1837).

     Lectotype ♂, designated by Cresson (1916: 111). USA, Colorado, Pike’s Peak [ANSP no. 2254].           

Taxonomic notes: The ♀ was descrubed by Michener (1947b: 303).

Though Michener (1947a, 1947b) considered Hoplitis argentifrons (Cresson, 1864) a valid subspecies of H. albifrons (Kirby, 1837) based on the larger proportion of dark pubescence on the face and dorsum of thorax in the female, it is clear that it is a highly variable, imtermediate taxon with some specimens approaching the fully melanic Hoplitis albifrons maura (Cresson, 1878) from California and Oregon, and some approaching the paler typical form, the latter is evidenced in the list of synonyms provided by Michener (1947b: 303), it is clear that this and the typical form (and its synonymies) have been used interchangeably in the past. Cresson (1864: 389) even suggested that his Monumetha borealis Cresson, 1864 might be the female for H. argentifrons, though its type locality in northern Canada supports the synonymy under H. albifrons. Titus (1906: 159) felt that Monumentha argentifrons was a synonym of M. albifrons (Kirby).

DNA Barcode Index Number (BIN): BOLD:AAB7508

This BIN is shared with Hoplitis albifrons albifrons (Kirby, 1837).

Distribution in Canada: Michener 1947 (BC, AB); Hurd and Michener 1955 [BC, AB]; Rowe 2017 [BC]; Sheffield and Heron 2019 [BC].

According to Michener (1947b: 302), in Canada H. albifrons argentifrons is found in southwestern Alberta and the southern half of British Columbia, while the typical form occurs east of the Rocky Mountains and into the north, though intermediate forms are known.