[Evolution of vitellins in the ovary and during development in three species of Diptera, Drosophila melanogaster, Calliphora vicina and Prasarcophaga argyrostoma].

The SDS electrophoresis reveals the asynchronous appearance of the three vitellins V1, V2, V3 during the ovarian cycle. It is always the V3 which appears first with the beginning of previtellogenesis. The vitellin degradation occurs late at the end of embryogenesis. The presence of a protein migrating at the level of V3 during the whole development is discussed.