We tabulated plant species that served as floral hosts of adult beetles as reported by Charles Robertson in his 33-yr data set of flower-visiting insects of central Illinois. Robertson listed 153 species of beetles (28 families) that visited 141 species of plants (44 families), most of which were in the Asteraceae. The most common beetle species were the cantharid Chauliognathus pennsylvanicus (De Geer), the chrysomelid Diabrotica undecimpunctata Mannerheim, and the scarab Trichiotinus piger (F.). Most of the beetle species (81%) were observed on five or fewer plant species. In general, non-native plant species were associated with fewer beetle species than were native plant species. Nevertheless, plant species that had the greatest diversity of beetle visitors were the non-native umbellifer Pastinaca sativa L. and the native rose Aruncus dioicus (Walter) Fernald variety vulgaris (Maxim). These findings may find application in guiding research on insect ecology and behavior, for selecting plant species in ornamental landscapes that will foster populations of native beetle species, and for identifying plant species that may be used in agricultural settings to improve pollination or biological control services.