Holey Grass

Don't take your shoes off in our yard, yet. Something has been emerging from the ground. There are holes bored about the size of a fat Kindergarten pencil every couple of feet. I don't think it's beetles, perhaps catapillars? Aliens? I don't know.
Where there is grass, it has greened up but as you can see there are still large patches of thatchy dead stuff. The clover has started up so maybe it'll fill in the holes.
I priced grass seed today at TSC but just got depressed about throwing more money away on the lawn.