Solenopsis saevissima, commonly known in Brazil as formiga de fogo, formiga-vermelha (red ant), or formiga-lava-pes, is one of more than 185 species in the genus Solenopsis. It, along with 13 other species, is also a member of the Solenopsis saevissima species group which are popularly known as fire ants. Although it is indigenous to South America, it has been apparently imported to Africa, Guadalupe and the Galápagos Islands. To date there is no evidence of it in the United States. S. saevissima is known for its powerful and painful sting, hence the name "fire ant". It is a pest in horticulture and one proposed method of control is to introduce the scuttle fly phorid into its habitat. Little information about S. saevissima and its behaviors is known or studied except from a few reports in Brazil and in French Guiana. The species is apparently all polygynous across the native habitat, and highly aggressive. Etymology The scientific name for Solenopsis saevissima comes from the , which means pipe or channel, opsis, which means appearance or sight and the Latin saevissima, which means "the very cruel". Its name derive of early accounts of its viciousness as reported from the Amazon forest. S. saevissima is named so because it is known to be even more vicious than S. invicta the red imported fire ants, which costs the United States millions of dollars per year in agricultural, medical, and traffic-related damage. Morphology S. saevissima belongs to the Solenopsis saevissima species group which includes 13 fire ant species that exhibit remarkably similar morphology, rendering morphological distinction nearly impossible without the aid of chemical characters. S. saevissima has polymorphic adult workers that differ in size depending on their castes: minor workers are generally smaller and major workers are relatively larger. The major workers also typically have trapezoidal heads and antennal scapes almost reaching their vertex; the minor workers have ovate heads and antennal scapes that extend past their heads. Like all species of the S. saevissima species group, S. saevissima has workers averaging 1.9 mm in length, antennae containing 10 segments, and mandibles with 4 or 5 teeth. Similarly to other species within Solenopsis, it has a conspicuous central hair on the front of its clypeus that extends beyond the outer margin of mandibles. Differently from most other species in the group, it lacks a well-developed medial clypeal tooth and its propodeum is rounded. Proper morphological