Pharaoh ants are very small, around 1/16 inch long. Most of them are yellow or gold in color. To properly identify these ants, you may need to talk to a experienced pest control service and/or use a microscope.
Pharaoh ants are very difficult to control for a number of reasons.
Most of the time, pharaoh ants will nest in an area that is dark and warm. More often than not, they will be nesting in a wall void. They do not live outdoors in this area and therefore, have to be brought in to establish a colony.
Since most pesticides only make the matter worse, the main thing to use is a food based bait designed for pharaoh ants. The worker ants will carry the bait back to the colony and directly feed it to other ants in the colony, including the queens. Baiting is the most effective way to treat for pharaoh ants, however, it may take anywhere from several weeks to even months to eradicate them.