About Andrena astragali Viereck & Cockerell, 1914
This bee species, Andrena astragali Viereck & Cockerell, 1914, displays clear physical differences between female and male individuals. Females measure roughly 10 to 13 millimeters long, have entirely black bodies, and are covered in hairs that range from reddish to creamy white. Males are slightly shorter, with body lengths falling between 8 and 12 millimeters. For all individuals of this species, the facial quadrangle is wider than it is long. Their wings are glassy with a faint reddish tint, have no dark margin along the edge, and appear dusky at the apex. Among other American Andrena species native to the western United States, A. astragali is distinguished by its larger overall size and the presence of two tooth-shaped projections on its labrum, the flap of tissue located in front of the mouthparts. It is visually most similar to Andrena fulvida, a bee species native to Europe.
