Hyperunstable mutations were described previously at the yellow locus of Drosophila melanogaster. These mutations are related to the insertion of the complex sequence containing two deleted copies of the P element at the termini and central unique regions from different sites of the X chromosome. In this work, double hyperunstable mutations at loci yellow and scute were obtained. These events were shown to occur from the inversion induced by the P elements located at the loci yellow and scute.