Wyeomyia smithii larvae were reared on 6 allotments of 7 larval diets. The allotments ranged from 0.125 to 1.5 mg of food/larva. Both the quantity and quality of the larval diet had a significant effect on larval development, adult fecundity and adult longevity. Larvae reared on Tetramin or a mixture of Tetramin and dog food developed faster and ultimately yielded adults that lived longer and produced more eggs. Fewer larvae developed to the pupal stage in the highest quantity of all diets tested but those surviving produced significantly more eggs as adults. Tetramin or a mixture of Tetramin and dog food at a rate of 0.5 to 0.75 mg/larva are recommended as diets for rearing Wy. smithii larvae. The effects of carbohydrate ingestion on adult fecundity and longevity also were examined. Fecundity and longevity were significantly greater for adults given access to a 10% sugar solution.