Another kind of bee rarely seen in person

This bee variety is sometimes called a solitary, leaf cutter, blue orchard, or a self employed bee.  It is really hard to get one of these to sting and I have never known it to happen.  They are startlingly iridescent in coloration from an emerald to a stunning, electric blue.  They live in holes in dead wood and seal them off with bits of leaf and mud.  They are much smaller than honey bees.

The top photo is the "hive" constructed to attract them to the yard.  The bees are rarely seen but the cut leaf margins on our climbing rose appear around the time they begin laying eggs in the five inch deep holes I drilled into the aged wood.  That seems to be the preferred plant for making beds for their larvae.  

The next photo is a close up of a few completely filled holes that are sealed off with mud.  There is a bowl full of mud and water kept at the base of the posts holding up the nest logs until midsummer.  There are about five larvae per hole and they will exit next spring about the time the apple blossoms happen.  Last year we had five holes filled.  This year we have eleven.