Catalog of Hymenoptera in America North of Mexico. 1979. Prepared cooperatively by specialists on the various groups of Hymenoptera under the direction of Karl V. Krombein and Paul D. Hurd, Jr., Smithsonian Institution, and David R. Smith and B. D. Burks, Systematic Entomology Laboratory, Insect Identification and Beneficial Insect Introduction Institute. Science and Education Administration, United States Department of Agriculture.
