Abstract
The weekly amount of eggs laid and the adult longevity were investigated in a stock of the melon fly, Dacus cucurbitae COQUILLETT, which had been mass-reared for about 54 generations since 1981. After the onset of mass rearing, the average amount of eggs laid gradually increased to 75ml/week/cage by the 14th generation, and reached a plateau thereafter. In the process of generations, the peak of oviposition came earlier and the longevity became shorter. However the total amount of eggs laid during the whole life span of the females was not reduced.
