ABSTRACT: 90 species of Euplectrus are treated: 55 newly described, all from Area de Conservación Guanacaste (ACG), and 35 previously described species, of which 20 occur in ACG. Three of the previously described species (Euplectrusbrasiliensis Ashmead, Euplectrushircinus (Say), Euplectrusronnai (Brèthes)) have unknown status, owing to missing or severely damaged type material. The new species, all authored by C. Hansson, are: Euplectrusalejandrovalerioi, Euplectrusalexsmithi, Euplectrusalvarowillei, Euplectrusandybennetti, Euplectrusandydeansi, Euplectrusannettewalkerae, Euplectrusbillbrowni, Euplectrusbobwhartoni, Euplectruscarlosarmientoi, Euplectruscarlrettenmeyeri, Euplectruscharlesmicheneri, Euplectruscharlesporteri, Euplectruschrisdarlingi, Euplectruschrisgrinteri, Euplectruscorriemoreauae, E
