Bumblebee pollinating Ladies'-tresses orchids in the Bog Garden

I went out to the front yard bog garden this afternoon, and I found dozens of bumblebees and honeybees frantically sipping nectar from the Spiranthes odorata or Fragrant Ladies'-tresses orchids. In the process, burying their entire heads in the flowers, the bees were pollinating each one they visited. I viewed one particular bumblebee annoyed with the pollinarium attached to its proboscis, rapidly swiping at the pollinarium until it fell to the ground.