At repeated sessions of the Permanent Committee of the International Office of Public Hygiene problems of the sanitary control of air navigation have received consideration, and it has increasingly become apparent that any set of just and reasonable regulations must be predicated upon facts established through researches and studies of factors relating to air traffic. Realizing the necessity for investigations on the subject, the United States Public Health Service began on July 23, 1931, the inspection, for the presence of mosquitoes aboard, of all aircraft 1 arriving at Miami, Florida, from foreign and insular ports. Strange enough, the first mosquito caught was an Aedes aegypti (male) on July 28, on the ship coming from San Salvador, El Salvador, C. A. with landings at Tela, Honduras; Belize, B. H., Merida and Cozumel, Yucatan. From July 23 to September 12, 1931, there were 102 inspections of airplanes just arrived at Miami from points in Panama, Central and South America, the West Indies, Cuba and Mexico.