Formica exsecta (the narrow-headed ant or excised wood ant) is a species of ant found from Western Europe to Asia. A rare formicine ant with a deeply excised head, F. exsecta forms small mounds up to around a foot in height consisting of much finer material than that used by "true" wood ants of the F. rufa group. An interesting feature of F. exsecta is that it comes in two distinct social forms. Either a monogyne form where the colony has a single egg-laying queen, or a polygyne form where many egg-laying queens are part of the same colony.