The excitant and repellent Effects on Mosquitos of sub-lethal Contacts with DDT

Abstract

1. Mosquitos often recover completely after showing the preliminary symptoms of DDT poisoning.2. The effect of contact with DDT on the activity and distribution of mosquitos has been studied in a small cage, exposure times being kept below that necessary to kill the insects.3. The duration of single resting periods on DDT-treated surfaces was several times shorter than resting periods on untreated surfaces, provided the mosquitos had had no recent access to DDT.4. Mosquitos that had been in recent contact with DDT rested only slightly longer on untreated than on DDT-treated surfaces.5. Mosquitos excited by DDT moved preferentially toward light.