Ecology of Andrena placida1 with Descriptions of the Larva and Pupa

Andrena placida Smith nests in compacted sand cliffs near the ocean in Marin County, California. The bees are vernal and polylectic. The chromosome numbers are n = 5 (♂) and 2n = 10 (♀). Comparisons with A. erythronii Robertson reveal that the 2 species are very similar in their biological characteristics and in structural features of their postdefecating larvae, and pupae.