Flora or Fauna?

I was taking time to get to know my yard and my 100 mm macro lens again when I spotted what I thought was an unusual flower. I got down on the ground, aimed my lens, looked through the viewfinder and was bowled over to see this sight. I watched for more than half an hour as 3 to 4 four enacted the same ritual over and over. They would land on the dead flower stalk, turn upside down and hold the stem with their mouth (or so it appeared) and then rub their legs on the stem and dead flower before rubbing their legs on themselves. They worked hard at this for quite a while. Then another bee would land and rub his legs on the bodies of all these other bees and then take off. The bees on the stem would then turn face up and groom their faces before resting in this pose. After a few minutes it would start over again. Sometimes one would fly away and one would arrive but there were always at least 3 bees doing this.

I did use flash since this was in the shade of late afternoon. My flash was set to its lowest setting and the background is the darkness of my screened porch.