1. By treating the silkworm eggs within 2.5 hours after laying with colchicine solution of various concentrations from 0.05 to 0.4%, many polyploid individuals were obtained.
2. Polyploid worms were detected both genetically and cytologically.
3. It is assumed that diploid and polyploid egg cells are mixed with one another in the ovaries of the polyploid individuals induced by colchicine treatment.
