Black flies are small, biting insects belonging to the family Simuliidae. They are commonly found near rivers and streams, where their larvae develop in clean, flowing water. Adult black flies are known for their painful bites, which they use to feed on the blood of mammals, including humans. These insects are most active during warm months and can be a nuisance in outdoor areas. Some species of black flies can transmit diseases to humans and animals, making them a concern for public health. Effective measures to reduce their populations include eliminating standing water and using insect repellents.