NOTE. I have redated this 2017 posting to make it appear closer to the other mason bee posts. I had moved all my Mason Bee Boxes inside in the late summer so am now extracting the cocoons and cleaning them up for storage in the refrigerator.
I was surprised how successful the longest tubes which I used (9 inches), have been this season. Below is a picture showing the number of cocoons I am regularly obtaining from these long tubes. 