A survey of Anopheles gambiae in Brazil was carried out in May, June, July, and the first week in August, 1939, months representative of the climate of the country at the close of the wet, and well into the dry, seasons. We were enabled to obtain in a comparatively short time a great deal of first-hand information about A. gambiae in Brazil and its effect upon the population as we were supplied with full facilities for transportation and field laboratories.
I. DETAILED STUDY OF A FRONTIER Opportunity for a full study of the advance of a species of anopheles into new territory is not often offered to the investigator, and is a matter of much sanitary importance. We have therefore described in some detail the frontier shown on the map, representing a portion of the Jaguaribe River above and below Iguatú in Ceará.