Key to Strumigenys species in or possible in the southeastern United States (adapted from Bolton 2000)
1  Antennae with 4 segments, the first funicular segment followed immediately by the two segmented club (FL)
  Antennae usually with 5 or 6 segments
....2
2(1) Leading edge of scape with all hairs curved toward apex of scape
...3
  Leading edge of scape with one to many hairs that distinctly curve toward base of scape
...5
3(2) First tergite of gaster densely covered with long, fine, flagellate hairs
  First tergite of gaster not densely covered with long hairs, but with simple, shorter, and more sparse hairs
....4
4(3) Mandible without intercalary teeth or denticles between apicodorsal and apicoventral teeth of the apical fork or at dorsal base of apicoventral tooth (FL)
  Mandible with 1 or 2 intercalary teeth or denticles that arise between apicodorsal and apicoventral teeth of apical fork, or arise from the dorsal base of apicoventral tooth (FL)
5(2)  

Mandible without intercalary teeth or denticles between apicodorsal and apicoventral teeth of the apical fork or at dorsal base of apicoventral tooth (also keys later, sometimes has denticles between apicodorsal and apicoventral teeth)
  Mandible with 1 or 2 intercalary teeth or denticles that arise between apicodorsal and apicoventral teeth of apical fork, or arise from the dorsal base of apicoventral tooth
....6
6(5)     Apical fork of mandible with a single intercalary tooth or denticle that arises between apicodorsal and apicoventral teeth, or arises from the dorsal surface of apicoventral tooth
.....7
  Apical fork of mandible with two intercalary teeth or denticles that arise between apicodorsal and apicoventral teeth, often represented by a distinct intercalary tooth accompanied by a less conspicuous denticle
7(6)     Ventral surface of petiole with spongiform tissue present beneath node; cephalic dorsm with a pair of erect hairs near highest point of vertex and another pair near occipital margin; eye with 15 or more ommatidia in total; larger species, HW 0.44 - 0.52 mm (TX)
  Ventral surface of petiole without a trace of spongiform tissue; cephalic dorsum lacking a pair of erect hairs near highest point of vertex, with a pair near occipital margin; eye minute, usually with a total of 4 ommatidia; small species, HW 0.33 - 0.37 mm (keys out twice)