When I think "dry humor", I think mostly of the delivery. Dry humor is definitely intended and deliberately delivered, but without any hint of amusement on the part of the deliverer. Whenever I see episodes from "All Creatures Great and Small" (one of the many BBC program(me)s that I love!), I thoroughly enjoy the multiple displays of dry humor in this superbly written and acted series.

On the other hand, to me "wry humor" is delivered with, at the very least, a twinkle in the eye, and possibly a nascent smile, and maybe even a wink, as the deliverer is thoroughly enjoying his/her own humor. It must also, in my mind, be witty and creative, so as to rustle the hair of some listeners, as they may notice its passing, but not quite understand what just whizzed by over their heads... :0)