Gerris is a genus of insects commonly known as water striders. These insects are characterized by their long legs, which allow them to walk on the surface of water. They are often found in ponds, lakes, and slow-moving streams, where they hunt for small insects and other prey. Water striders belong to the family Gerridae and are known for their unique ability to exploit the surface tension of water. They can be recognized by their slender bodies and the way they glide effortlessly across the water's surface, making them fascinating creatures in aquatic ecosystems.