This large fly flew in through an open door. The first impression, of course, was that it was a wasp. But right away I knew it was a fly just by the sound it made in flight. It flew slowly for a fly, but its large size slowed it down. As it bumped up against a window again and again our cats were very intrigued, but they were fooled by the colors and size and were very cautious. I took this close up picture when it paused for a breath. The wings and eyes were also a dead giveaway to its true nature. I had never seen anything like it before; of course I have seen many of the small type that immitate bees, but its size and coloring were quite surprising. It was truly at least an inch in length. I eventually just cupped it in my hands and took it outside to finish its job of pollinating our roses. Please help in its identification.