You nailed it, Dillard. I dug the old pack out and it is indeed Butter Belly. Yellow Belly really doesn't sound like a good name, eh?
I've never been able to spot a moth. It seems for me that I never have a problem with them until *just before* they start making squash. Great-looking plants one day, then the next day a total collapse. I'll inspect these closer this year, but won't be going to very much trouble with them. Who knows, I might be fortunate with these this year. Most likely I will have to do my crookneck harvesting at the farmer's market!