Key to US Ponera species

Key to Ponera species of the United States based on workers.

1

 * Larger in size, the total length greater than 3 mm, head width greater than 0.42 mm, or cephalic index (head width X 100/head length) is 76 or less, or both; hairs on gastral dorsum vary in size from 0.04-0.1 mm; color medium to dark brown => Ponera pennsylvanica


 * Smaller, total length less than 2.5 mm, head width either 0.35 mm, or less or cephalic index is 79 or greater, or both; the hairs on the first gastral tergite about 0.02 mm and bristly in appearance; color yellow to pale brown => Ponera exotica