Abstract
Plexippus setipes was reared under constant temperature (27-28°C) and photo-peried (16 hours each day), and the following results was obtained.
1. The spiders moulted 5 to 6 times before they reached adulthood.
2. Durations of days in each instar were greatly affected by the food condition, the duration was shortened when feeding interval became short.
3. Total number of days required for the development from the first instar to adult was 110-200 days, excepting the period of immature nymphal stage staying in egg-sac.
