A mosquito survey, having as its object an enquiry into the distribution and prevalence in certain Far Eastern Ports of Stegomyia fasciata, the known carrier of yellow fever, was begun, on behalf of the Imperial Bureau of Entomology, by Dr. A. T. Stanton, whose report was published in the Bulletin of Entomological Research (Vol. x, pt. 3). As it seemed unlikely that he would be at leisure to complete the observations by a survey of the ports of China and Japan, as had been planned, the writer was instructed, in April 1921, by the Government of the Federated Malay States, at the suggestion of the Imperial Bureau, to complete the enquiry.