Abstract
This Is the first of a series of papers intended to present results of biological studies by the authors on various aculeate Hymenoptera and their parasites. The present study was made at Antioch, Contra Costa County, California, during the summer and fall of 1938, and the spring of 1939. We have found the works of Fabre (1908), Ferton (1923), and Rau (1918) particularly useful in providing a source of corroborative data on the habits of bembicid wasps and we would refer the reader to these papers which are cited in the bibliography.
