ABSTRACT
Fire ants are members of Solenopsis, which is one of the largest ant genera in the world, comprising approximately 160 unchallenged species and a great many more in collections waiting to be described. Leaf-cutting ants comprise 24 known species of Acromyrmex. Fire ants and leaf-cutting ants are thus seen to be among the most advanced social insects that arose in the New World, most likely in South America when that continent was isolated from the remainder of the Western Hemisphere. The specimens, which are beautifully preserved, include a typical fire ant worker, as well as several small "thief ants". The truth is that we know very little about the evolution of defense in myrmicine ants. So unusual is unique adaptation and so successful have been the ants possessing it that it can be properly called one of the major breakthroughs in animal evolution.
