Bulletin - United States National Museum (G.P.O, 1962)

Bulletin - United States National Museum (G.P.O, 1962)

Bulletin - United States National Museum (G.P.O, 1962)

Bulletin - United States National Museum (G.P.O, 1962)

Hymenoptera of America north of Mexico : synoptic catalog, second supplement - Krombein, Karl V. (U.S. Dept. of Agriculture, 1967)

Hymenoptera of America north of Mexico : synoptic catalog, second supplement - Krombein, Karl V. (U.S. Dept. of Agriculture, 1967)

Hymenoptera of America north of Mexico : synoptic catalog, second supplement - Krombein, Karl V. (U.S. Dept. of Agriculture, 1967)

Hymenoptera of America north of Mexico : synoptic catalog, second supplement - Krombein, Karl V. (U.S. Dept. of Agriculture, 1967)

Proceedings of the Entomological Society of Washington - Entomological Society of Washington (Entomological Society of Washington, 1957)

Proceedings of the United States National Museum - Smithsonian Institution (Smithsonian Institution Press, [etc.], 1960)

Proceedings of the United States National Museum - Smithsonian Institution (Smithsonian Institution Press, [etc.], 1960)