M.D.
I have had these ants for a couple of years. Found out they are Pharaoh ants. Look them up online and see if they look like what you have. When you spray, they know their colony is under attack and make lots of satellite colonies and then come back in other places with a vengeance. Apparently you have to bait them to get them to take the poison back to the entire colony to really get rid of them. Terro works well sometimes, but they weren't always attracted to it, and they still kept coming back. I finally gave in and called an exterminator. He sold me a product called Advance Dual Choice bait, which seems to be really working. The ants swarmed most of the stations that I put out, and now I haven't seen any more in several weeks. I even put some on the outside where I saw them entering my house, and when I went back to check the baits, not only were the Pharaoh ants taking the bait, but the fire ants were, as well! Good luck!!