Myrmecia similllina is a species of ant that can have both monogynous and polygynous colonies. The colony size can reach several hundred workers. They have a medium development rate. The queen measures 20-24mm in size, while the workers measure 16-22mm. They have a dark red color with a black belly and strong, sickle-shaped jaws. They consume food insects like cockroaches and crickets, as well as fruit and syrup. The ideal humidity level for this species is unknown.