There is a spray that we bought from home depot to kill them. I think its made by zep. We came home from vacation one year and our basement was full of them. My dad and I would walk in and look down a minute later and we could see them on our legs. We tried the bug bombs but they didn't work. that spray stuff did. you have to apply it every day i think. It looks like a bottle w/ a tube and spray nozzle on the end..kind like a thing of roundup. You just have to spray it everywhere.