...a report soon followed that Mr. Bingley was to bring twelve ladies and seven gentlemen with him to the assembly. The girls grieved over such a large number of ladies; but were comforted the day before the ball by hearing that, instead of twelve, he had brought only six with him from London, his five sisters and a cousin. And when the party entered the assembly room, it consisted of only five altogether; Mr. Bingley, his two sisters, the husband of the oldest, and another young man. (P&P, Chapter 3)
So, what happened to Bingley's other 3 sisters and cousin? We never, ever hear about them again.
Were they figments of imagination, like the 12 ladies of the original report? Or were they younger/still in the school room and therefore technically didn't exist in society yet? I can't think of any other reason they were entirely invisible after that one, brief, line.
I've wondered about those missing sisters for years and welcome any and all opinions. :-)