Andrena are an extremely diverse group of common ground-nesting bees. They have a near-cosmopolitan distribution, and several species can be found across the Holarctic region. They vary greatly in size, pilosity, flight period, dietary and habitat preference. Females typically have two patches of short, velvety hairs alongside the compound eyes (“facial foveae”) and pollen brushes that cover the hind legs almost completely, sometimes even extending to the sides of the propodeum. Males of this genus are highly variable in appearance and lack common distinctive characters. They have glands on their jaws that produce species-specific secretions which they use to mark the landscape and attract females.Their nests are typically excavated in light soils and, despite having a solitary lifestyle, they can sometimes form massive aggregations.