Perhaps Margined Calligrapher, the Calligrapher flies I see most frequently here. This fly was hovering over a Mexican Hat I was photographing and I did not see it until I looked at my photos.
on echinacea purple coneflower
On Narrow Leaf Milkweed in my yard. Maybe a Margined Calligrapher since I have seen a number of those in my yard.
Kishwauketoe Nature Conservancy