Sweat Bee
Lasioglossum ?
Gathering pollen from the stamens of Sacred Datura (Datura wrightii). Phoenix, Arizona, 12 April 2014.
Halictidae -- Sweat Bee Family
Many native bees, as opposed to the ubiquitous Honey Bee, are small. This one is similar to bees in the genus Lasioglossum and is less than 4 mm long.
The females bees provision their individual nest-tunnels, usually built in the soil, with mixed pollen and nectar. In the case of the flower at left the bee is gathering only pollen because the nectar is contained deep in the flower base where the bee cannot reach it. She will have to visit other types of flowers to gather nectar.