Nice catch Perry. Thanks for the pics.
Perry.... Please excuse the following comments. Posted for member's info.
With large swarms, I have shaken the swarm into an empty swarm box then gently rested the frames (one at a time) on the bees. The frames slowly sink into the bees.
I like to place the box holding the swarm several meters away from the swarm tree. I like to think that the stragglers have a distinct location from the swarm tree.
An air freshener block, hung in the tree where the swarm was, seems to help the stragglers go to the fanning swarm box, which I leave til dark before closing and removing.