The arguta species-group

Tergite 1 narrowly and shallowly emarginate at the apex, or apex nearly straight; tergite 2 with medial impression; tergite 1 with long basal discal carinae. Small, shining, and dark brown (3 species) or brown (1 species). Species included are: B. arguta (Casey), B. elegans (Brendel), B. terebrata (Casey), and B. wickhami Bückle sp. n. This group is common in northeastern North America, with one species known only from Arizona.