Guess what happened all week?  Tons of flies rested on our screen door just waiting for it to open and shut.  Unless we made an exit at lightning speed, the flies just zoomed in.  One evening at bedtime, an incredible number of buzzing, black flies had accumulated inside the RV! They were on the ceiling, the furniture, and everywhere!  I was not going to sleep with them inside, so we got out the vacuum cleaner!   Using the hose, we turned the situation into a game and began counting. We sucked up almost 100 flies!!!