With over 850 species, the genus
Nomada is one of the largest genera in the family
Apidae, and the largest genus of
cleptoparasitic "cuckoo bees". They occur worldwide, and use many different types of bees as hosts, primarily the genus
Andrena. As parasites, they lack a pollen-carrying
scopa, and are often extraordinarily
wasp-like in appearance, with red, black, and yellow colors prevailing, and with smoky (infuscated) wings or wing tips.