The significance of insecticide-resistant strains; with special reference to pests of medical importance.

The author discusses the meaning of insecticide resistance and the manner in which it should be detected and measured. From some recent data he gives a number of examples of measurements of resistance in mosquitos of different species in various areas. He then proceeds to a speculative discussion on the way in which insecticide resistance arises, whether it can be prevented and overcome, its importance in the past and at present, and finally its future prospects.