This report is a detailed account of the following first three major points regarding all the contributions on silkworm genetics from this laboratory since 1945. 1. Features on newly discovered genes were explained in each linkage group. Characters on a number of genes which were found previously have also been detailed. 2. Linkage groups of many genes were determined and also new linkage groups were established. 3. Studies on chemical induced mutations by means of specific loci method on egg colour genes have been described. The chemical mutagens used in these experiments were Melamine, Triazine derivatives, 4-nitroquinolin-N-oxide and its related compounds, Alkylbenzensulphonic acid and Triaminobenzen. 4. A case of genetical expression of malformation induced in eggs treated by organic phosphate-insecticide has been explained from the point of view of effectiveness of selection.