MR. F. G. SAREL WHITFIELD has recently issued a comprehensive article on air transport, insects and disease (Bull. Entomol. Res., 30, 365–442; 1939). The discovery by Shannon in 1930 of the presence of Anopheles gambiæ, an insect native to Africa, in the city of Natal, Brazil, and its subsequent spread, directed special attention to the carriage of disease-bearing insects by aeroplanes. Whether A. gambiæ was actually transported in a surface vessel or in an aircraft will probably never be known, but, as the result of its entry and subsequent spread, more than 90 per cent of the population around Natal were infected with malaria in 1938. The indexes of malaria-infected mosquitoes are said to be the highest in the history of malaria. The introduction of A. gambiæ into South America seems to have had the disquieting results, just referred to, because possibly the native population has very little power of resistance to the African strain of the disease carried by the mosquito.