The Milwaukee Public Museum Invertebrate Zoology Collection numbers about 800,000 specimens of which 70% are insects and 30% are other invertebrate groups encompassing a broad diversity of animals (52 zoological classes.) Lepidoptera and Coleoptera comprise the largest portions of the insect collections, and Mollusca and Crustacea the largest collections of other invertebrates. Special insect collections include the Type Collection (about 60 holotypes and 55 syntypes) of various orders, tropical Lepidoptera and gynandromorphs from James R. Neidhoefer, a worldwide collection of Sphingidae from William E. Sieker, the Albert Schwartz collection of West Indies Lepidoptera, determined Costa Rican cacao-pollinating midges (Ceratopogonidae and Cecidomyiidae) from Allen M. Young’s research. Other significant invertebrate collections include a comprehensive survey of WI crayfishes made by the WI Department of Natural Resources, Horton H. Hobbs III and Joan P. Jass, the Harold Mathiak collection of WI freshwater unionids, and the WI arachnid collection, including the historically important George W. and Elizabeth G. Peckham Collection of jumping spiders. A more detailed description is available at http://www.mpm.edu/research-collections/invertebrate-zoology/collections-overview. For further information or loans, please contact Collection Manager Julia Colby (colby@mpm.edu).