ABSTRACT The subjects which are about to engage our attention have been under investigation for many months. They comprise the following points : 1. The scarcity of Stegomyia fasciata on non-infected fruit vessels from ports quarantined against yellow fever. 2. The scarcity of cases of yellow fever on fruit vessels from ports quarantined against yellow fever. 3. The impunity of intercourse with fruit vessels at the city wharf before the holds are fumigated. 4. The Stegomyia fasciata on non-infected fruit vessels from ports quarantined against yellow fever are not infected. 5. The improbability of stegomyia on infected fruit vessels becoming infected before arriving at the quarantine station. 6. The impossibility of mosquitoes on infected fruit vessls to carry yellow fever to the city before the arrival of the vessel at the city wharf. 7. The cases of yellow fever found on fruit vessels were infected ashore.I.—SCARCITY OF STEGOMYIA FASCIATA ON