The purpose of the study was to establish the importance of single and multiple blood meals taken by a vector in the development of larval filariae, dwelling in tissues other than the fat body. The black eye strain of Aedes aegypti was used as experimental vector for Brugia malayi and Dirofilaria immitis, filariae species which develop in the flight muscles and malphighian tubules respectively. Under similar conditions, both filariae species molted for the first time on the 6th day and a second time on the 10th day, approximately. Mosquitoes took an infective blood meal through a membrane feeder and were subsequently maintained on 10% sugar water alone (group A) or received supplementary blood meals i.e., an uninfected blood meal before the first molt and another after it (group B), an early blood meal (group C) or a late blood meal (group D). It was observed that larval development to the 2nd stage was similar in all groups of both filarial species. Early and repeated blood meals were the most desirable nutritional schemes for the rapid maturation of D. immitis while a late blood meal appeared to yield the best development of B. malayi larvae. Both species of filariae from mosquitoes maintained on sugar water alone showed an uneven and slow rate of development. It is concluded that nutrients other than carbohydrates are the important factors for the rapid growth of filarial larvae.(ABSTRACT TRUNCATED AT 250 WORDS)