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Margana Walker Gen. rev.
Type
species: seclusalis Walker, Java.
This
genus is revived for a small complex of species currently combined with Egnasia (Poole, 1989). Though the facies and wing shape bear a
general similarity to those of Egnasia, the forewing
underside has the orbicular stigma conspicuously pale, rather than the reniform.
The two
other small Bornean species with a pale orbicular on the underside that were
placed in Egnasia by Poole are
assigned to the next two genera. These share this feature of the orbicular and
also the lack or considerable reduction of the phragma lobes on the second
abdominal tergite, but differ in features of their genitalia. The labial palps
in all three genera are long, slender, gently upcurved.
The
male eighth segment is atypical, the tergite being slightly framed and the
sternite broad, very flimsy, without definite structure. The genitalia have a distinct
gnathus that is longer than the uncus. The posterior margins of the tegumen
have a central triangular process. The valves are short, obliquely trilobed
distally, and there is a distinctive transtilla dorsal to the anellus with
prominent digitate processes dorsally in a ‘V’. There is also a transverse
bridge between the valves ventral to the anellus.
The
female genitalia of tenuilinea Swinhoe (see the taxonomic note for that species)
lack the clear features of the Episparis group but share
with Throana Walker the dragging of the ostium with the eighth
sternite anteriorly into the position of the seventh sternite, which is
vestigial to absent. The apodemes of the eighth segment are absent in seclusalis and typical tenuilinea but smaller and
pulled anteriorly in the Bornean specimen tentatively associated with tenuilinea.
The
ostium is wide, the ductus short, entering almost
immediately into a rather elongate corpus bursae that is ornamented with panels
of sclerotisation and areas of scobination. Externally similar specimens from
Peninsular Malaysia (slide 19246) and W. China (slide 17593) represent further
species and have the anterior migration of the ventral part of the eighth
segment less extreme, though the seventh sternite is still vestigial. The
ductus bursae is longer and narrower in both species (very narrow in 19246),
and the corpus bursa more ovate and intensely scobinate. The ductus seminalis
arises from near the apex of the corpus bursae.
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