Ants of the genus Colobopsis are common inhabitants of twigs throughout North and Central America. The queens and major workers plug the entrance to the nest, and have to receive a signaling code from one of the foraging ants before they will back up, open the nest entrance hole and allow the worker to enter the nest. Although they are very interesting ants, very few studies have been done on their biology and behavior. We hope that this identification guide may allow these ants to be more thoroughly studied.