Diagnosis. The male labial palps are as in the previous two species, but the antennae are strongly bipectinate as in the next three related species; the foreleg is less tufted, most of this associated with the tibia. The forewings are coloured as in alpheusalis, but the fasciae are more oblique, straighter, convergent towards the dorsum, the postmedial more sinuous rather than stepped, or even almost straight. The hindwing has two rather obscure pale fasciae rather than just the broken submarginal of alpheusalis.
Taxonomic note. The lectotype of phlegeusalis (UM, Oxford) was illustrated by Owada (1992), with the indication that it was part of the Bertula generic complex. The secondary sexual characters, the forewing facies and the general features of the male abdomen relate this species to alpheusalis, though the male foreleg lacks a spur on the first tarsal segment. The male genitalia have a short, bifid valve, scobinate in the centre, and a small spiny process subapically on the dorsal side of the aedeagus. A male from 1000m (see below) showed slight variation of the former feature but not the latter. The short, bifid valves of the male with the sacculus fused to the juxta and, in the female, a distinctly modified and sclerotised ostium and sterigma, together with the bipectinate male antennae and general facies, define a small group of species, three out of four of whichoccur in Borneo. The fourth is described next.
Geographical range. Borneo.
Habitat preference. The type material of both synonyms was taken in Sarawak by A.R. Wallace, probably in the lowlands, Four specimens were taken during the Mulu survey in forest at 130m, 150m and 1000m. Three further females have been taken from: Bidi in the lowlands of Sarawak; a Paraserianthes falcataria plantation near Brumas in the lowlands of Sabah.
