Diagnosis. See gravatalis above, and comments below on the female.
Taxonomic note. Swinhoe (1900) placed this species as a synonym of gravatalis, though it is treated as distinct by Poole (1989). The type material consists of two male syntypes in BMNH and a female, noted as a ‘var.’ in the original description, in OUMNH. The female matches gravatalis in external features (see above), but the males represent a distinct species as discussed here. Therefore the male syntype labelled as ‘Type’ is here designated LECTOTYPE. A female specimen tentatively associated with erythusalis here is larger than the males, the forewings a more uniform grey, especially over the medial area, which is only slightly paler than the areas to either side of it.
Geographical range. Borneo.
Habitat preference. This species has a similar altitude range to gravatalis, though it is perhaps more common in the lowlands. Several specimens were also taken at 1780m on G. Mulu, and the female attributed was taken at 1000m.
