This is a deer fly, probably in the genus Chrysops, laying eggs on a blade of grass at the edge of a small man-made pond in North Carolina near Highlands.
The location marker is very approximate. I was on Little Scaly Mountain's north flank, at The Mountain Retreat and Learning Center's little swimming pond. If you are ever in NC you should drop by The Mountain, a very beautiful place with excellent facilities for conferences or personal retreats.
Other photos showed the rows of eggs better, but then of course the fly's head was out of focus.
It was odd to stumble upon this event, truly the most sacred milestone in a fly's life, and one that most never get old enough to experience!