Cephalotes pusillus, commonly known as turtle ants, is a species in the subfamily Myrmicinae, part of the genus Cephalotes. These ants are famous for their distinctively shaped heads and their arboreal life style. Workers have a flattened, disc-like head, which they use to block nest entrances as a defense mechanism. Cephalotes pusillus ants are strictly arboreal, meaning they spend most of their lives in trees. They build their nests in hollow branches, cavities, or in other naturally occurring crevices in trees.