Hi Valerie, Thanks for sharing this photo with us and our friends. Yes this tiny little wasp is a parasitic wasp of mason bees (and other insects). You can see from the size of the cocoon in the background how tiny this critter really is! At the moment that this picture was taken, this wasp was listening for bee movement inside the cocoon ( it hears with its antennae). Only live bees are parasitized!! Great picture Valerie.