Pseudomyrmex flavicornis (F. Smith, 1877)
Worker diagnosis. HW 0.99-1.21; head broad (CI 0.83-0.94); median clypeal lobe laterally rounded; frontal carinae relatively well separated (FCI > 0.06); head densely punctulate and opaque; head, postpetiole and gaster black or blackish-brown, mesosoma and petiole varying from black to reddish-brown.
Distribution. Guatemala to Costa Rica.
Biology. This is an obligate acacia-ant, which has been recorded from Acacia collinsii, A. cornigera and A. hindsii. Colonies are monogynous.