Diagnosis of worker among Antkey species. Head shape triangular. Antenna 6-sgemented. Antennal club 2-segmented. Antennal scapes not conspicuously short; easily extended beyond eye level. Antennal insertions at least partly covered by frontal lobes. Eyes medium to large (greater than 5 facets); situated on lower margin of scrobe. Frontal lobes do not obscure face outline between mandible and eye. Posterolateral corners of head unarmed, without spines. Mandibles linear; armed with small denticles. Pronotal spines absent. Propodeum armed with spines or teeth. Waist 2-segmented. Spongiform lacking from petiole and postpetiole. Appressed circular hairs do not cover face, mesosoma and waist segments.
Strumigenys eggersi can be separated from other introduced and commonly intercepted Strumigenys species by the following combination of characters: (1) mandibles linear; (2) mandibles with denticles, lacking apical fork; (3) appressed circular hairs do not cover face, mesosoma and waist segments; and (4) spongiform lacking from petiole and postpetiole. Strumigenys gundlachi is appears similar, but S. eggersi is distinguished by the complete lack of spongiform on the waist (versus spongiform present on postpetiole).