Amdro is the corn meal type. It is a bait, so you have to wait for the ants to carry it back to the mound. If you can still find it, Orthene is the stuff that will kill off quicker. But its pretty nasty stuff. Its like a white talcum and stinks to the high heaven. I usually mix it into a sprayer and spray down all my foliage to keep the ants off (and any other critter) and drench the mound. But, if you (AND YOUR NEIGHBORS) stay on top of the situation, you should not have to worry too much. Otherwise, they just move back and forth across the yards.
I guess Lubbock hasn't had a really good cold spell for a few years to kill the little beasties off. Was nice and cool (102) when I was there a few weeks ago.[8D]