Mosquito larvae and pupae which get their oxygen from aquatic plants have been seldom met with so far; all belong to the genus Taeniorhynchus. Examining Pistia for the latter I found a few times a larva attached to the roots of the plants by means of its modified air-tube. The adults which were bred from these larvae proved to be Ficalbia (Mimomyia) hybrida, Leicester*. The adult has been known for some time, but the larva is new.