Summary From January, 1952, through April, 1953, a series of dissections of wild-caught anthropophilic mosquitoes for larval worms resembling Wuchereria bancrofti was performed in Marshall Territory, Liberia. Advanced-stage infections were found in Anopheles gambiae, A. melas, and A. hancocki. In addition, natural infections have been found in A. funestus in a nearby locality in Liberia. No advanced-stage infections were found naturally in any culicine mosquito. Five species of laboratory-reared indigenous mosquitoes were fed on a human donor with microfilariae of W. bancrofti. A. gambiae, A. melas, and Culex thallasius were readily infected and carried the infection to maturity within thirteen to fourteen days. Culex fatigans and Aedes aegypti became infected in a much lower percentage, and development of the worms tended to be slower. In all three culicine species, many young nondeveloping larvae were noted in the thoracic muscles. In the small series reported here, Anopheles melas was more heavily infected with the intermediate stages of W. bancrofti in nature than Anopheles gambiae.