Abstract
An electrophoretic key is described which permits individual larvae, pupae and adults of 9 species of Rhagoletis Loew to be distinguished. The key is based on the mobilities of 6 enzymes, separated by gel electrophoresis. Individuals of 4 of the 5 species which infest cherries can be distinguished, as can the 3 sympatric eastern U.S. species of theR. pomonella sibling species complex.