Phidippus audax (Hentz 1845) was observed in the field and tested in a laboratory in order to estimate its use of two locally abundant, soft-bodied coleopteran species, Diabrotica undecimpunctata (Chrysomelidae, Galerucinae) and Chauliognathus pennsylvanicus (Cantharidae). In the field, Phidippus audax was most commonly observed hunting on leaves or stems of the common milkweed and feeding upon species of Diptera or Diabrotica undecimpunctata. Despite high densities of Chauliognathus pennsylvanicus, P. audax was never observed feeding upon this species. In laboratory feeding trials, P. audax always retreated from C. pennsylvanicus and always attacked D. undecimpunctata. Also, P. audax retreated from models displaying the markings of C. pennsylvanicus in 88% and attacked models displaying the markings of D. undecimpunctata in 85% of the laboratory trials.