Key to Cyphomyrmex  species in the southeastern United States (from Snelling and Longino 1992)

1          Small, head width 0.56 mm or less; hairs in center of first gastral tergite closely appressed, usually separated by more than their own lengths; median basal groove on first gastral tergite short and not obvious
  Larger, head width 0.62 or more; hairs in center of first gastral tergite not completely appressed, usually separated by less than their own lengths; median basal groove on first gastral tergite twice as long as wide, distinct