Zethus pygmaeus Zavattari, 1912: 12 (key), 32 (male, in division Zethusculus). Bohart & Stange 1965: 23 (reaching southern boundary of North American Tropical Area), 160 (key), 165 (Figs 139–142), 167 (male; female; in subgenus Zethoides; El Salvador, Panama, Peru, Brazil), 204 (fig. 341). Rasmussen & Asenjo 2009: 43 (Peru). Type data: Holotype male, Genoa [MSNG]. Type locality: “ Peru: Pevas”.
Examined material. 2♀, 2♁ (see Supplementary Material 1). PERU: ♁, holotype, Loreto, Pebas [MSNG]. BRAZIL: 1♀, São Paulo, Onda Verde [BME], 1♁, São Paulo, Santa Rita do Passa Quatro [RPSP]. PARAGUAY: 1♀, Canindeyu, Res. Nat. Mbaracayú [DZUP].
Distribution. El Salvador, Panamá, Peru, Brazil (Mato Grosso, *S„o Paulo), * Paraguay (Bohart & Stange 1965; and new data).
Observations. Bohart & Stange’s (1965) species key runs this species as having one mid-tibial spur. However, examination of the type revealed it to actually have two spurs. Additionally, this species is recorded in S„o Paulo State, Brazil and Paraguay, which are further South than previous records in the literature.