Summary and Conclusions During the course of three experiments undertaken to test the flight of Stegomyia aegypti, in which over 20,000 stained specimens were released in small villages, two specimens were recovered in houses at a distance of more than 300 meters from the point of release, while 95 were taken at intermediate points. Another lot of 12,000 mosquitoes was released on a boat 900 meters distant from one shore and 300 meters from the opposite shore. Of these, eight were recovered on shore at an approximate distance of one kilometer from the boat. Less than 0.4 per cent of the entire number of released mosquitoes was recovered. The latest capture made was thirteen days after the date of release (experiment I). After a week's time all stained specimens became exceedingly scarce. This indicates either that dispersion is very thorough, widespread, and rapid, or that mortality is very high. From the foregoing, it would appear that a flight of more than 300 meters is not exceptional among the stegomyiae of a representative community; and a sustained flight of one kilometer over water is well within the range of possibility.