Abstract
This paper reports the results of observations made during the summers of 1971 and 1972 on a small group of Bembix americana Fabricius nesting in a vacant lot in Seattle, Washington. This population was judged to be intermediate to comata Parker and spinolae Lepeletier at the subspecific level (H. E. Evans, pers. comm.).Probably no North American digger wasp has been more thoroughly studied than B. americana (Evans 1957, 1966; Evans and Matthews 1968). However there has only been one report of this. species making nests with more than a single call (Parker 1925). Evans (1966) notes the uniqueness of this account and the difficulty of accurately digging out nests in dense colonies. Nevertheless in the course of my work I discovered that some of the wasps in Seattle were making multi-celled nests. The evidence for this is presented here as well as data on the nest building behavior of marked females over a period of time.