The ovarian development and blood-feeding of Phlebotomus bergeroti were investigated using a laboratory colony derived from Egyptian flies. Most (89%) of the females in this colony were autogenous. The level of ovarian development observed at the time of blood-feeding varied between Christophers' stages IIB and V, indicating that vitellogenesis did not inhibit blood-feeding and that the females that ingested blood before their initial egg-laying were facultative, not obligatory, blood-feeders. The females ingested blood 2-8 days after they had emerged, the probability of a female taking an offered bloodmeal being highest between days 4 and 7 post-emergence. Blood-feeding significantly increased fecundity, significantly reduced the number of eggs that were not laid although apparently mature, and decreased the mean duration of the gonotrophic cycle by almost 1 day. Bloodmeals increased fecundity by stimulating the previtellogenic primary follicles of the autogenous females to precipitate yolk, possibly by initiating concurrent vitellogenesis in the primary and secondary follicles of the same ovarioles. Autogeny in P. bergeroti probably has little influence on the transmission of Leishmania parasites by this species.