Despite illustrations in Garman (1926) clearly showing the different antennal appendages of Eubranchipus vernalis and Eubranchipus neglectus, Creaser (1930) published erroneous drawings of the antennal appendages of these two species that led to more than 65 years of taxonomic confusion between them. We untangle this confusion, and show that these species have nonoverlapping areas of occurrence with E. vernalis to the east and E. neglectus to the west of the Appalachian Mountains. In addition, we present evidence supporting the use of resting-egg (cyst) morphology in studying evolutionary relationships among anostracan species. An important part of this usefulness is due to the independence of cyst morphology from sexual selection. Since the primary taxonomic characters of anostracans are all strongly influenced by sexual selection, cyst morphology can supply a reasonably independent set of characters for testing hypotheses of species relationships.