Details are presented of some experiments conducted to observe the behavior of Anopheles larvae when the surface tension of water is reduced. Larvae fail to cling to the surface when the surface tension reaches a critical range, 27 to 36 dynes. Individual larvae show small differences in behavior and there does not appear to be any difference in the minimal surface tension requirements of larvae of several species studied. Surface tensions of natural waters do not reach the low minimal ranges required to drown larvae. A study of several types of habitat indicates that surface tension is not a factor determining distribution of species.