Metamorphosis Interrupted

Every year at this time, a couple of large bees that make a loud buzz come to my wooden deck slats and bore holes into the wood on the bottom side of the slats.
The sawdust falls onto my deck surface. I assume the bees lay the eggs and house them in the holes until the eggs reach the larva stage of metamorphosis. I know the bees destroy the wood on my deck. They also like to dive bomb me when I get too close to the wooden slats.

Something interrupted this year.
This is a pic of the larva and sawdust that I found on the deck the other day. The larva and sawdust out of the holes. They are motionless. I don't see the bees anymore.
The next day after this pic, the larva is gone but the sawdust remains.
Hmm...
Sylvia
www.sylviabrownroberts.com