I saw two of these flies on separate plants, both exhibiting the same behaviour - dancing around a stalk, separating their wings, then one appeared to curl its body (I assume to lay eggs). I couldn't capture the beauty of the cream and white edged wings - I've never seen a fly with dark, opaque wings. Hope they're native!
Thank you Michael - the fly is an amazing creature! And thank you for all that you have done for NM, the work you've put into moderating 40,000 +++ sightings, and taking the time to comment and share your knowledge.