1. Chemistry Department, The University, Calgary, Alberta T2N 1N4, Canada, on leave at the Entomology Division. D.S.I.R.
2. Entomology Division, D.S.I.R., Private Bag, Auckland, New Zealand
3. Horticulture and Processing Division, D.S.I.R., Auckland, New Zealand
4. Chemistry Division, D.S.I.R., Lower Hutt, New Zealand
5. Max-Planck-Institut für Verhaltensphysiologie, D-8131 Seewiesen, German Federal Republic