Guenee (1858: 360, pl. 20, fig. 2) described a new genus and new species, Rhopalodes castniata Gn., basing on a single female specimen from Brazil. He paid much attention to the unique character of antennae, which are cylindrical, thickening from base to apex like in Castniidae and ending in a pointed tip just like in some Hesperiidae (Rhopalocera). In the descriptions of the following genera, Sauris Guenee and Remodes Guenee (Guenee, 1858: 361-364), the author paid attention to very long palpi of moths, to the presence of a 'lobe appendiculaire' in the males of the described species, but mentioned also the presence of one pair of spurs in the hind legs of Sauris (like in Rhopalodes) and the absence of spurs in Remodes.
Snellen (1874: 77, pl. 6, fig. 2) presented the first description of a male from another species, Rhopalodes patrata Snellen, corrected one error by Guenee (concerning hind legs of Rhopalodes, which bear two pairs of spurs) and paid attention to the analogous shape of the antennae in the oriental species of Remodes.
The publications on further species, Rhopalodes lobophoraria Oberthur from Peru (Oberthur, 1881: 37, pl. 10, fig. 10), Rhopalodes argentina Berg, 1883 and R. muscosaria Berg, 1885 from Argentina (Berg, 1883: 164, 1885: 273) were fairly detailed, whereas the following descriptions by Dognin and Warren concentrating on the wing pattern (Lobophora ebriola Dognin, 1892, Lobophora? parecida Dognin, 1892, Lobophora rosula Dognin, 1892, L. ligereza Dognin, 1893 from South Ecuador) resulted in that Rhopalodes seminivea Warren, 1900 from Bolivia and R. variegata Warren, 1900 from South Brazil appeared later synonymous with, respectively, R. ligereza and R. argentina (Scoble, 1999).
Later on, Warren (1904, 1907), Bastelberger (1908a, 1908b), and Dognin (1911, 1913 (as Anaitis subrufata), 1923) added descriptions of new species of Rhopalodes from Peru, Bolivia, Paraguay, Ecuador, and Colombia. Prout (1910) described one additional species from Argentina and commented the build of antennae within the genus, noting that their subapical thickening is not universal in Rhopalodes. Warren (1900, 1904, 1907) classified Rhopalodes in his subfamily Trichopteryginae.
A total of 16 species are now grouped within Rhopalodes (Scoble, 1999). A large anal lobe in the modified male hind wing (although small in R. otophora Prout, 1910) and fine pointed antennae are distinguishing characters for the genus. The species of the southern group, inhabiting Argentina, Paraguay, and Bolivia (P. argentina, P. muscosaria, P. otophora), appear smaller in size and predominantly grey-patterned on wings, the Andean complex of the species (now mostly pictured on the BOLD taxonomy homepage (http://www.boldsystems.org/views/taxbrowser (visited 31.07.2011)) and that of the Simpsonian Institution (USNM Geometridae Primary Type Specimens, http://entomology.si.edu/Lepidoptera/geos/ Collections_Leps_GeoTypes.html (visited 31.07.2011)): P. nigrifasciata Bastelberger, P. patrata, P. subrufata Dognin in Colombia; P. ebriola, P. ligereza, P. parecida, P. rosula, and P. uniformis Dognin in Ecuador; P. concinna Dognin, P. lobophoraria, P. perfusa Warren, and P. vexillata Bastelberger in Peru) being larger in measurements and more variegated in pattern, including rosy or red elements on wings. The olive green pigment, which is often prevalent in the ground colour of wings, seems apt to fading due to moisture and/or during time in collections. The new taxon Rhopalodes lecorrei shares its variegated facies with montane species.
Recently, Parra & Santos-Salas (1991) redescribed Rhopalodes, adding genitalic sketches for two species (R. argentina and R. castniata). Pinas (2006) pictured R. patrata Snellen and another, unnamed species from Ecuador. The former species is distinguished from the new one by the course of the antemedian border of the medial area of the forewing, slanted towards the tornus between the discal cell and the hind margin of the wing (compare pl. …