Techniques are described for mass rearing Anopheles freeborni. Eggs were incubated overnight at ca. 28 degrees C and then dried. Measured quantities of dried eggs were placed into styrofoam rings floating on the water surface of rearing trays. Water levels in larval rearing trays were kept shallow, and temperature was maintained with heat tapes at ca. 28 degrees C. Larvae were fed once a day on a slurry containing a 3:1:1:1 mixture of guinea pig chow, liver powder, yeast and hog chow. Pupation began on the 7th day after egg hatch, and pupae were harvested on the 8th, 9th and 10th days; ca. 1,700 pupae were harvested/tray. Adults emerged from 85% of the pupae, and about 40% were female. Individual males held in gallon-sized containers inseminated as many as 10 females. Although most sugar-fed males died within 2 weeks after emergence, over 35% of sugar-fed females survived for 3 weeks. Colonies were maintained on defibrinated bovine blood provided in natural membrane prophylactics. There were no significant differences in the number of blood-fed females or in the number of eggs they produced when mosquitoes were offered either guinea pigs or defibrinated bovine blood. Eggs were collected in plastic cups placed in cages. There was less than 6% mortality of eggs when these were dried and stored at 10 degrees C for 6 days.