This paper presents descriptions of three new species of Ephemeroptera from Illinois, all belonging to the genus Ephemerella. These are forms segregated from material in the Illinois Natural History Survey collection; the types are deposited in that collection. Two of these species are closely related to the genotype, E. excrucians Walsh, and it was thought for some time that one or the other of them would prove to be that species. Study of the lectotype of excrucians showed, however, that both of these species are recognizably distinct from excrucians.