Abstract
The adults of Thysanoplusia intermixta (WARREN), visiting the flowers of Abelia grandiflora REHD. were collected in Fukuoka, and from these adults the eggs were prepared. The eggs, larvae and pupae were reared in incubators at 18, 20, 25 and 30°C. From the relationships between temperature and developmental velocity, the threshold of the development and thermal constant for completion of immature stages were calculated as 7.0°C and 580-625 day-degrees, respectively. From the seasonal prevalence of the adult emergence and the egg densities, four generations were recognized from June to October. In addition to these generations, the adult emergence of the overwintering generation was estimated in the period from April to early May in Fukuoka. The adult population densities were highest in the 1st and 2nd generations, and lowest in the 3rd generation.
