This species, which is native to Argentina and Brazil, was probably introduced at New Orleans via coffee ships from Brazil before 1891. Argentine ants are found in the southern states and in California, with isolated infestations in Illinois, Maryland, Missouri, Oregon, and Washington.
Body varies from light to dark brown.
Antenna 12-segmented, without a club. Thorax lacks spines, profile unevenly rounded . Pedicel 1-segmented . Gaster with anal opening slitlike, lacking circlet of hairs . Stinger absent but can bite on provocation.