Synonyms and other taxonomic changes
the genus is divided into species groups rather than subgenera
>280 spp. in our area, >700 spp. worldwide/total(2)
Most are small or medium in size.
Wasp-like, often red or red and black and often with yellow integumental markings. Others are yellow and black or have white markings instead of yellow. Females have specialized hair patches at the tip of their abdomen whereas males have a conspicuous pygidial plate, often notched.
Most species fly in spring but some fly in summer and fall.
Cleptoparasites on other bees, most often Andrena but also including Agapostemon, Melitta, Eucera, and Exomalopsis. Both sexes visit open flowers such as composites for nectar.
Cleptoparasites of various bees, primarily Andrena but also Agapostemon and Eucera (Synhalonia) (these are usually larger than the Andrena cleptoparasites). (J.S. Ascher, 23.iv.2008)
Males mimic the specific odors of the host females and patrol the host nest site(3)
Alexander, B. A. 1994. Species-groups and cladistic analysis of the cleptoparasitic bee genus Nomada
(Hymenoptera: Apoidea). University of Kansas Science Bulletin 55: 175-238. (Full Text
Alexander, B. A., and M. Schwarz. 1994. A catalog of the species Nomada
(Hymenoptera: Apoidea) of the world. University of Kansas Science Bulletin 55: 239-270. (Full Text