Quadristruma emmae (Emery, 1890) [Invalid]

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 apical fork. Pronotal spines absent. Propodeum armed with spines or teeth. Waist 2-segmented. Petiole and postpetiole with distinct spongiform. Appressed circular hairs cover face, mesosoma and waist segments.

Strumigenys emmae can be separated from other introduced and commonly intercepted Strumigenys species by the following combination of characters: (1) mandibles linear; (2) mandibles with apical fork, not denticles; (3) appressed circular hairs cover face, mesosoma and waist segments; (4) spongiform on petiole and postpetiole. Strumigenys hexamera is superficially similar because it also has appressed circular hairs, but S. emmae is easily distinguished by the mandibles armed with an apical fork (versus denticles).