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Oeonistis
Hübner
Type
species: entella Cramer, India.
Synonym:
Philagria Kirby (type species entella
Cramer).
This
genus contains four more or less allopatric species ranging from the Indian
Subregion to Samoa, Tonga and Queensland. All species (except lifuensis
Rothschild where markings are reduced) have a similar distribution of
blue-black on the forewing, particularly the stepped medial bar and the more
irregular submarginal zone, the apical ellipse of yellow being similar to that
of Monosyntaxis females. The venation is illustrated in Fig 1g.
Fig 1g: Oeonistis
entella Cramer
The
male genitalia have a reduced saccus as in Monosyntaxis
and a similar aedeagus, but the valves are more elongate, the saccular
process robust, broad, not falcate, apically setose or spined. Two of the four
species (entella Cramer, delia Fabricius)
have a furca-like structure, particularly well developed in delia.
The
female genitalia have a short, sclerotised ductus, sometimes with a colliculum,
and an elongate, pyriform corpus bursae with a single, strong, scobinate signum
centrally at the widest part.
The
New Caledonian and Loyalty Island species, lifuensis
Rothschild, was recognised as distinct from what was then considered to be
the widespread entella Cramer by
Viette (1950), who illustrated its genitalia with those of delia Fabricius stat. rev. Dissection now
indicates that entella is in fact a
complex of three species.
True
entella (syns. convoluta Fabricius, entelliola
Hübner) appears to be restricted to S. India and Sri Lanka. The male
genitalia are distinguished from those of altica
Linnaeus by an acute but setose apex to the saccular process and a pair of
prominent, dark, finely setose ear-like lobes in a furca-like structure.
The
Bornean species is altica Linnaeus,
with China as type locality (Mikkola & Honey, 1993), having similar male
genitalia to entella but lacking the
furca lobes and having the apex of the saccular process of the valve rounded,
with a serrate row of short spines round its extremity.
The
third species, delia Fabricius (syns. ceramensis
Vollenhoven, splendens Lucas, braeckeli Debauche), ranges from Sulawesi eastwards to New
Caledonia, Samoa and Tonga, and is characterised by long furcal arms and a
broad, biangular saccular process in the male genitalia. The type material of delia
consists of two unspread females in the Banks Collection in BMNH, with the
type locality ‘Insula Amsterdam’. There are several contenders for this
locality, including the ecologically unlikely one in the S. Indian Ocean that
still bears this name. Others listed in gazetteers were located off Sri Lanka
and Java, and as a European name for Tongatapu in Tonga. Dissection of one
syntype (BM arctiid slide 4911) revealed it to be damaged internally but to have
sufficient of the sterigma and structures posterior of it to show that it had a
flocculent, ring-like structure at the distal end of a pleat running back from
the sterigma. This is a feature of the eastern widespread species (e.g. seen in
a specimen from Vanuatu; slide 4829), hence the Tongan option for the type
locality is probably correct.
The
early stages of entella have been
described by Hampson (1900) and Bell (MS). Hampson described the mature larva as
having a reddish brown head, and the skin of the body ochreous, mottled with
black dorsally and brown elsewhere. The tufts of setae on verrucae are grey and
brown, those on T1 directed forwards. The dorsal verrucae on T2 have very long
setae, and those on T3 arise from a crimson wart and are also long. The dorsal
tufts of abdominal segments are shorter, arising from orange warts, except on A4
where the warts are again crimson. There is a prominent dorsal tuft on A8
arising from a large wart; the lateral tufts tend to be long and the sublaterals
short.
The
eggs (Bell, MS) are laid in batches of over one hundred on the underside of
leaves, more or less in rows and narrowly separated one from another. They are
round, with hexagonal dents in irregular concentric circles around the micropyle.
Hampson
(1900) noted lichens as the larval food.
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