Which of the following flies develops their larvae in fast moving water?

The black fly is the correct answer because its larvae are specifically adapted to develop in fast-moving water environments, such as streams and rivers. These larvae require well-oxygenated water to thrive, which is a characteristic feature of flowing water habitats. Black flies are known for their association with aquatic environments, which plays a crucial role in their life cycle as they undergo several growth stages in these conditions.

The other types of flies listed, such as the house fly, stable fly, and blow fly, typically do not have larvae that develop in fast-moving water. Instead, their larvae are usually found in more stable environments where there is organic matter or decomposition taking place, such as in garbage, animal waste, or decaying materials. Understanding the specific habitat preferences of different fly species helps in managing their populations and addressing potential pest issues effectively.