part_of frontal triangle Frontal triangle- A small triangular patch of the cuticle located mediodorsally on the head immediately behind the clypeus and approximately between the antennal sockets or anterior parts of the frontal carinae in many ant taxa. (Bolton, B. (1994). Identificstion guide to the ant genera of the world. Cambridge, Mass., Harvard University PRess. pp.1-222). SIBO:0000088 sibo head