 | Hymenoptera of America north of Mexico | (1) |
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 | Hymenoptera of America north of Mexico : synoptic catalog, first supplement / prepared by the staff and collaborators of Hymenoptera Unit, Insect Identification and Parasite Introduction Laboratories, Entomology Research Division, Agricultural Research Service under the direction of Karl V. Krombein. Washington, D.C. : U.S. Dept. of Agriculture, 1958. | |
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