The report is concerned with taxonomic studies of adult and immature Trichoptera in the southeast and several aspects of the ecology and distribution of southeastern aquatic insects. The distribution of the family Hydropsychidae in the Savannah River basin in relation to water quality parameters was studied. The effects of prolonged exposure to a chlorinated hydrocarbon insecticide, dieldrin, and its effect on aquatic insect populations and residue levels are discussed. The feeding habits and feeding rates of an herbivorous stonefly were studied as well as the effect of such feeding on water quality--such as increased leaching from leaves as a result of insect feeding. In conjunction with the preceding laboratory experiments, an extensive study was carried out on the benthic fauna of four small streams of various plant cover types in southern Applachians. The pine stream had lowest diversity and standing crop biomass, whereas the coppice had greatest standing crop biomass.