These are the most frequent house flies in our house. They come in from the outside and fly around the windows seemingly trying to get out. Very annoying. Occasionally they land on food that has been left out like hamburgers. We see them almost every day.
Large numbers of these beetles were hovering over the grass. I've never seen so many Japanese Beetles in one place. The baseball fields may have a hard time with their grass in the next few years. These beetle larva feed on the roots of grass. They are a major horticultural pest.