About 4 years ago came home to find a ton on the ceiling right inside the french doors. They leave an orangey mark and smell like potatoes. I tried everything and finally had to call an exterminator. They use pyrytheum (sp?) to kill them.
He said they come when it begins to get cold and can get into very small openings. Some years I had them others I don't. I'm in VA and he said the best thing to do is spray the perimeter of your foundation, around windows and doors in August before the weather begins to get chilly (here that's just before our fall). Helps kill off the larva also. (I've had some limited success with Home Defense that you can buy at Walmart, Lowes, etc).
I had a bee infestation in my home vent system last year and now have a yearly contract with a national exterminator company. It's actually cheaper to do that than it would be for them to come to your home more than once a year. A yearly contract means they come every 3 months and any time I may have a specific problem.