This paper is largely a report of definitely observed and demonstrated flights of Anopheles albimanus Wiede. and its racial variety tarsimaculata Goeldi. Darling (1912) has shown that these two species are the most important ones in the transmission of malaria on the Canal Zone. Albimanus is by far the commonest Anophelene about settlements, but at times, and locally, the race tarsimaculata appears in large numbers. At the salt-marsh northwest of Gatun, breeding of these two forms was so vigorous (apparently demoralized) that unlimited variations in the middle white band on the palpus were noted, this band being often represented by only a few white scales. For all practical purposes, however, these two forms may be considered as a single species.