In habits this fossorial wasp very nearly approaches the dividing line between the true fossorial and true parasitic wasps. It was discovered at Urbana, Illinois, October, 1934, in cornmeal as a parasite of the common saw-toothed grain beetle, Oryzaephilus surinamensis (Linn.). As very little work had ever been done on the habits of this parasite, it was considered appropriate to study its biology in detail. The problem was done under the supervision of Dr. C. L. Metcalf, Head of the Department of Entomology, University of Illinois, to whom the writer is greatly indebted for many valuable criticisms and suggestions.