Thank you for that information! It was most helpful.
I also received a reply from an Entomologist:
Entomology (Study of Bugs)/Answered Question
Expert: Ed Saugstad
Subject: Black Polycaon Beetle?
Answer: Dear Walter - This does indeed appear to be a black polycaon beetle, Polycaon stoutii (Coleoptera: Bostrichidae). However, as long as the wooden surfaces in your office are coated in some fashion (varnish, shellac, paint, etc.) they are not in danger if infestation by these beetles - female beetles first “taste” the wood to determine whether it contains enough starch and sugar to nourish their offspring, and if the wood surface is coated, they cannot taste it and will not lay eggs. And you are correct in believing that once the wood is placed in water that you should have no more problems with these beetles. Should any adult beetle be able to emerge before the wood becomes completely saturated, it will float to the surface where it can be scooped out and destroyed. See http://tinyurl.com/68hdv
for more detailed control recommendations for wood-infesting beetles in general.
Hope this helps,
Much of the stand is made of exposed plywood and pine on the inside, and there are large access holes in the back inside. My desk is made of oak. Inside of both - the wood is not stained/varnished. I'm going to apply the Borax solution just for my own peace of mind. Once it is treated, and it sinks into the wood, it will be good for years of protection.