In studies of the microbial control of the Formosan subterranean termite.Coptotermes formosanasShiraki, it was found that the mere introduction of even a highly virulent pathogen directly into the galleries of the termite was not sufficient to initiate epizootics in the colonies. Colonies ofC. formosanusin Hawaii are very large and extensive with galleries radiating out 50 m or more (Zimmerman 1948; Bess 1970). Therefore, because of the distances involved, the pathogen could not be spread easily from the exposed gallery to the main nest.