The decrease in Anopheles quadrimaculatus prevalence, which began in late July, continued generally through September. This is shown graphically by the accompanying chart. Drought and the advent of cooler weather tended to diminish breeding in some of the areas; in others the pooling of streams and the stabilization of pond and lake surfaces have increased the control problem. Entomological reports (M-7) received during the month show that in a total of 480 or 92 percent of the zones, quadrimaculatus densities were satisfactorily low. This compares with 91 percent in this category during August. The number of satisfactory zones had increased to 94 percent by the last week in September. Inspectional and control work was discontinued in several of the more northerly zones during the month.

David J. Sencer CDC Museum