1. Stern, C.: Genetic Mosaics and Other Essays. Cambridge: Harvard Univ. Press 1968.
2. Gehring, W., Nöthiger, R., in: Waddington, C. H., Counce, S. J. (Eds.): Developmental Systems. Insects. New York-London: Academic Press (in press).
3. Lindsley, D. L., Grell, E. H.: Genetic Variations ofDrosophila melanogaster. Carnegie Inst. Wash. Publ.627 (1968).
4. Fox, D. J., Abächerli, E., Ursprung, H.: Experienta27, 218 (1971).
5. Dickinson, W. J.: Genetics66, 487 (1970).