1. Visiting Scientist, Laboratory of Entomology, Wageningen University, P.O. Box 16, 6700 AA Wageningen, the Netherlands.
2. Chemicals and Health Branch, United Nations Environment Programme, International Environment House 1, Chemin des Anémones 11-13, 1219 Châtelaine, Switzerland.
3. Anti-Malaria Campaign, Ministry of Health, 555/5 Elvitigala Mawatha, Colombo 00500, Sri Lanka.