Frontal carinae
Description:A pair of longitudinal ridges on the frons, behind the clypeus and between or often partly covering the antennal fossae. Their length is variable: they may be absent or vestigial to very long, extending back to the posterior cephalic margin. They are often expanded anteriorly to form the frontal lobes. In some ant taxa, they may be the dorsal margin of the antennal scrobes.