The biology of citrus butterfly was studied under laboratory conditions on sweet orange. Adult female laid eggs singly or in groups of two to five on the under surface of tender leaves and also on tender twigs. Oviposition usually took place during the night. The average number of eggs laid by a gravid female moth was 112 eggs. Based on the observations made in this study it is concluded that the average incubation period lasted for 2.90 days with a range of 2.75 to 3.00 days. The average first, second, third, fourth and fifth in star larvae lasted for 1.82, 0.86, 1.52, 1.99 and 2.42 days, respectively. The average total life cycle of citrus butterfly on sweet orange lasted for 20.64 days with a range of 20.00 to 21.00 days.
