This approx 1.5 " flying pest is digging holes in the slots between my patio slate squares and boring out sand mounds on to the top of the slate on my patio. How do I get rid of them? Where else might they live?
The insect in your photo is a cicada killer wasp. They are beneficial wasps that help to keep the cicada population down. They nest in dry sunny areas and are not particularly aggressive. They should be tolerated if possible.
There are no easy control solutions. Modify the habitat and make the area unattractive to burrowing. Sweep the sand back into the slate cracks.
In lawns thicken your stand of turf by overseeding in the fall. Reduce exposed soil in ornamental beds by planting groundcovers and applying mulch. In new beds pin down landscape fabric with landscape pins and cover with mulch.
Here is more information about them on our website
More links https://entomology.ces.ncsu.edu/2015/07/cicada-killers-are-on-the-wing/