Bornealcis Gen. n.
Type species: expleta Prout.
The three species in this genus are of delicate build, with very similar
facies to several Alcis species in the brown forewings with angled or
sinuous fasciae and reddish or yellowish orange hindwings. But species such as A.
semiclarata Walker (Himalaya), A. cockaynei Prout and A.
hemiphanes Prout (Java), and A. subtincta Warren and A. semiochrea
Prout (Luzon) have male genitalia typical of Alcis, close to those of
the A. variegata Moore group that includes the Bornean A.
The male antennae have the pectinations apical to each segment as in Alcis,
and there is a setal comb on the third sternite.
In the male genitalia the juxta is as in Rikiosatoa, with a pair
of very long filaments arising from a pouch between the bases of the valves,
asymmetric with a pair of more robust spines, also asymmetric, in the type
species. Uncus and gnathus are long, slender, the former not hooked; socii are
present, most strongly in the type species. The valve is slender with a cucullus, but lacking other processes except in B. versicolor Prout
n. where there is a small lobe subbasally, centrally. The aedeagus is rather
slender, the distal opening distinctively oblique. The vesica is small,
corrugate scobinate with a dense mass of fine spicules.
In the female genitalia the ovipositor lobes are narrower, acute. The
lamella postvaginalis is transversely pleated. The ductus is short, it and the
base of the bursa sclerotised and scobinate or pitted. The bursa is narrow,
elongate, ringed distally with two bands of widely spaced coarse teeth in the
type species but immaculate in B. versicolor.
The genus is a member of the Alcis, Rikiosatoa and Pseuderannis
Inoue group of Sato (1984a) but combines the juxta characteristic of the
second without its diagnostic antennal feature. The extreme reduction of valve
processes, the slender, sclerotised uncus and gnathus, the modified aedeagus and
the ornamentation of sterigma and ductus appear to be diagnostic.
The three species are all endemic to Borneo and montane.
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