part_of frontal carina Frontal carinae- A pair of longitudinal ridges on the head, located dorsally behind the clypeus and between the antennal sockets. They are very variable in the length and strength of development, frequently being short and simple but sometimes extending back to the occipital margin of the head. In some groups the frontal carina are vestigial or absent, but elsewhere they may be strongly developed or form the dorsal margins of extensive antennal scrobes. Commonly the frontal carinae anteriorly are expanded into progecting lobate extensions, the frontal lobes, which partially or entirely cover and conceal the antennal sockets. Frontal lobes may be the only expression of the frontal carinae in some groups. Sometimes the portions of the torulus closets to the cephalic midline is raised and expanded into a small, laterally projecting lobe, which may extend beyond the lateral margin of the frontal carina or lobe. (Bolton, B. (1994). Identificstion guide to the ant genera of the world. Cambridge, Mass., Harvard University PRess. pp.1-222). sibo SIBO:0000085 Frontal lobes head