JOHN G. HILDEBRAND Research on insect olfaction is important for at least two reasons. First, the olfactory systems of insects and their arthropod kin are experi- mentally favourable models for studies aimed at learning about general principles of olfaction that apply to vertebrates and invertebrates alike. Detailed comparisons between the olfactory pathways in vertebrates and insects have revealed striking similarities of functional organisation, physiol- ogy, and development, suggesting that olfactory information is processed through neural mechanisms more similar than different in these...