Unfed 2- to 5-day-old starved females and 12-day-old sugar-fed females of various species of Florida mosquitoes were fed ad lib. a meal of chicken blood to repletion and analyzed for the amount of blood ingested, egg maturation and production, and energy reserves in spent females and in eggs laid. Sugar-fed females of these species, with the exception of Aedes asgypti and Anopheles quadrimaculatus, attained considerably greater wet weight (1.2 to 1.6 times) and dry weight (1.4 to 2.1 times) and ingested considerably smaller quantities of blood (wet weight—0.5 to 0.9 times, dry weight—0.6 to 0.8 times, and calories—0.6 to 0.8 times) than starved females of the same species. In all species, except Aedes sollicitans, the number oocytes matured and the number of eggs laid in sugar-fed females were considerably higher than in starved females. In general, starved females retained more matured oocytes after completion of egg laying than sugar-fed females. Two to 3 times more blood per 100 eggs laid per female had to be ingested by starved females as compared with sugar-fed females. In all species investigated, sugar-fed females had considerably more glycogen and triglyceride reserves remaining after laying a batch of eggs than starved females, which indicated that sugar-fed females could live much longer after oviposition than starved females. No distinct differences in energy reserves were observed in eggs laid by starved and sugar-fed female Ae. sollicitans and Psorophora confinnis. Eggs from starved Ae. aegypti females sugar-fed Aedes taeniorhynchus females had much more energy reserves than their corresponding groups. These studies clearly demonstrate the importance of sugar-feeding in addition to blood-feeding for longevity and fecundity of mosquitoes.