The percentage of the diseased female moths of silkworms always diminished with high speed in accordance with retardation of eclosion date irrespective of the difference of maturation days of larvae and their combination like that of the previous experiment (OHSHIMA et al., 1966c). In the case of male moths, their diminution velocity fairly decreased and became somewhat irregular. Comparing the result of the present experiment with that of the previous, there exist two great differences: (1) The percentage of diseased female and male moths of larvae that ripened early was inferior to that of the larvae that ripened late in the present experiment, while it was just the reverse in the latter. (2) Reversal in the percentage of diseased male moths occurred only on the day near the end of eclosion where their number greatly diminished in the former, if it happened, while it always occurred on an intermediate day where a great many moths eclosed. When a room was continuously lightened by the electric lamp every night from 0 hour until day break, the eclosion time of diseased female moths moved up and it happened earlier by repeated lightening, but in the case of diseased male moths, this phenomenon was not so conspicuous as that of the diseased female moths.