The Balloki, Pakistan, strain of Culex tritaeniorhynchus required 4 days from first to last cohort pupation when reared under laboratory conditions of 16:8 LL:DD with a 1.5 hr simulated dusk and dawn and 28 C. Larvae began to pupate before the simulated evening crepuscular period and finished after the beginning of complete darkness. Pupal ontogeny took 25.38 hrs for males and 25.48 hrs for females regardless of the time when pupation occurred. Male terminalia rotation commenced 3 to 4 hrs after 19 hrs. Males were not able to inseminate females successfully until they were at least 26 hrs old, and 50 hrs were required for 100% cohort sexual maturity. Females were inseminated as early as 8 hrs after emergence, but an estimated 59.3 hrs were required for cohort maturity. Gravid females of mixed ages exhibited a triphasic oviposition rhythm with most egg rafts produced during the simulated evening crepuscular period. Secondary peaks occurred at 0200 and 0600 hrs.