About Erebus caprimulgus (Fabricius, 1781)
Erebus caprimulgus has a wingspan measuring approximately 90 to 104 millimeters. This species displays clear sexual dimorphism. In males, vein 3 of the hindwing runs to the functional apex of the structure. The costal fold is not developed, and the granular patch is small. Veins 4 through 8 of the male hindwing are moderately developed within the aborted costal area. It is similar in appearance to Erebus hieroglyphica, but differs from that species by the presence of a large whorl on the forewing and the absence of a yellow sub-apical bar. The anal segment of the abdomen has tufts of orange hair surrounding the claspers. Females are generally similar in appearance to males, but have an indistinct antemedial line on the forewing, plus an additional line running from the whorl to the inner margin of the forewing. Hindwings of females show faint traces of a sinuous medial line. Some morphs of this moth have a broad, sinuous postmedial line on both wings, which angles near the costa of the forewing. The outer area of the wings in these morphs is suffused with grey, or sometimes the outer area of the hindwing is mostly white. Another morph is brownish overall, with wings suffused black extending out to the postmedial line. The ventral side of both wings features an irregular postmedial series of white spots.
