This PMD emerger in size #16 imitates a pale morning dun struggling to hatch in the surface film.
PMD hatches bring reliable summer dry-fly action. Dead-drift it to risers during the emergence.
Present it with a drag-free drift, mending your line as needed to extend the drift through the feeding lane. It also makes a highly visible top fly in a dry-dropper rig, pulling double duty as strike indicator.