Abstract Staminodeus, new genus, is described for seven species: S. inermis, new species, from Panama; S. curvitibialis, new species, from Colombia and Venezuela; S. denticulatus, new species, from Costa Rica and Panama; S. bispinosus, new species, from Panama; S. forcipis, new species, from Costa Rica; S. dilatatus, new species, from Panama; and S. vectoris, new species, from Costa Rica and Panama. Staminodeus is placed in Derelomini, and is characterized by the putative synapomorphies: carinate rostrum, male with prothoracic leg ventrally denticulate (excepting S. inermis) as well as median lobe internally with complex structures, and female with frontal spine. All species are hypothesized to be associated with the staminodes of the inflorescences of Cyclanthaceae. Field observations on the reproductive behavior of S. vectoris at La Selva, Costa Rica, indicate that the protibia in males is used to displace competitors, whereas the spine in females was used as a point of support while transporting the de...