Proceedings of the eighth International Conference on Ephemeroptera and the twelth International Symposium on Plecoptera held in August 1995 in Lausanne. The latest findings on the freshwater insects emphasize their important role as bioindicators. The articles in this book include studies on their life histories, feeding and behaviour patterns worldwide, and point out fluctuations in their biodiversity due to their sensitive reactions to varying environmental factors. Taxonomy and modern phylogenetic theories are also discussed.