Nyceryx janzeni (Taxonomy)
Most similar to Nyceryx stuarti but smaller (on average, about 1 cm), ground colour of forewing upperside paler brown, and upperside of body paler, lacking purplish sheen and with the last two segments not significantly darker than the rest. Similar in size to Nyceryx riscus but distinguished by the paler forewing upperside, less contrasted transverse lines and the narrower submarginal zone, the inner edge of which is almost straight and has a uniformly narrow and well defined dark line basally. Forewing upperside similar to Nyceryx stuarti but paler and lacking the purplish sheen of the majority of specimens of that species; discal spot conspicuous, white (in Nyceryx stuarti, the discal spot is brown and very inconspicuous); inner edge of submarginal area straight between Rs4 and CuA2 and bounded basally by a well defined, narrow black line (in Nyceryx stuarti, the inner edge of the submarginal area is evenly, if shallowly, curved and is bounded basally by a broader black line of irregular thickness; in Nyceryx riscus, the inner edge of the submarginal area is even more strongly curved and the basal black line even wider, often strongly triangularly expanded on M3). Hindwing upperside similar to both Nyceryx stuarti and Nyceryx riscus but basal yellow area broader and outer edge more convex between M1 and CuA2. 25 mm.Wingspan: 55-60 mm (average = 57 mm, n = 10). Similar to Nyceryx stuarti but:Uncus strongly indented in dorsal view, bearing on each side a rugose, spatulate, setose process (in Nyceryx stuarti and Nyceryx draudti, this process is longer and twisted; in Nyceryx riscus, it is more heavily sclerotized, straight and pointed).Gnathos with apical hooks more evenly circular in outline in lateral view; in dorsal view, they are visible between the uncus processes and the anal tube.Aedeagus with a shorter smooth apical point (unlike the spinose process of Nyceryx riscus).