1. Observations on the bionomics of Chrysomyia rufifacies Macq. in India have been recorded.
2. Protein is essential for the maturation of eggs, which is complete in about 5 days after emergence.
3. Mating is necessary for oviposition, though egg formation can proceed independently of mating. A single mating is sufficient for at least three batches of eggs.
4. Eggs hatch in 8–12 hr. after they are laid.
5. The average number of eggs produced is 210 (bred flies).
6. The development from egg to adult occupies about 9½ days in summer.
7. The larva is semi-carnivorous, and the floor of the pharynx is provided with ridges.
8. Females of this species produce offspring of one sex only, either all males or all females. This phenomenon, which is independent of diet and of season, is extremely rare among animals especially as parthenogenesis does not occur in this insect.