This communal North American bee lives in underground nests which females may use over multiple years. Nests can reach a depth of 60cm and 40 or more females may be found living in one nest. Males emerge from the nest first in the Spring, females about a week later. Mating pairs can be found near nest sites, often on flowers. Females then spend 1-2 months collecting pollen, which they bring back to the nest to provision the cells where their offspring are developing. The nests are sometimes also occupied by other bees (eg: Nomada cressonii) and parasitic Bombyliid flies. (Osgood, 1989)