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Narosa Walker
Type species: conspersa Walker.
Synonym: Penicillonarosa Strand (type species: penicillata Strand).This
genus is one of several with a deep costal area of the forewing, a sinuous vein
R1 (e.g. Fig. 33) and filiform antennae. It is characterised by
forewings with a complex series of pale and dark orange fasciae, in particular a
broad, dark though centrally pale bar arising just postmedially and obliquely
from the costa, extending roughly half way to the tornus, where it is truncated,
though often continuing in separate rows of dark orange flecks postmedially and
submarginally.
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Narosa
concinna
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In the male genitalia the majority of species, though not conspersa, have
some sort of process from the valve sacculus. In the female the ductus is
distally spiralled, and the bursa contains a lenticular array of numerous
stellate signa extending over almost the whole length.
The mainland Asian group associated with Penicillonarosa such as ochracea
Hering have no saccular process and a distinctive row of spines on disc-like
bases in the aedeagus vesica.
Two Bornean species belong to a Sundanian group within a wider complex
characterised by a deepened, rather balloon-like apical portion to the valve,
seen at its simplest in the Himalayan species N. endodonta Hampson. This
is sister to a group extending from Sundaland eastwards where the valve apex is
bibbed. This group in turn is divided into: a Sundanian group, (concinna,
velutina), where the simple saccular process of the valve seen in endodonta
and the most easterly species becomes extended asymmetrically, sclerotised
and scobinate, the gnathus is apically bifid and the upper lobe of the valve is
larger; a group consisting of N. pectinata Hering from New Guinea and a
species complex from Sulawesi where the aedeagus apex is cupolate; and a further
pair from Sulawesi. This group of Narosa is discussed further by Holloway
(in press).
There is little information on the early stages of the genus, though
Bell (MS) reared conspersa. The larva is semi-ovoid, but dorsolateral
ridges come to an angular rounded point, so that the lateral outline is
triangular, the dorsal plan oval, and the transverse section a laterally
truncated, slightly curvilinear-sided triangle, knobbed where truncated. The
body surface is shining, pitted, the segments separated by frosted ridges, part
of a complex, almost reticulate system of ridges. There are no tubercles but a
few hairs. The colour is green, the main dorsolateral ridges yellow, their
highest point tipped rose-pink; there is a double grass-green spot in each
dorsal diamond formed by the ridge system and another on each segment outside
the dorsolateral ridges; there is yellow on some intersegmental ridges and a
series of lateral and marginal yellow spots. This pattern is somewhat variable.
The larva lives on the undersides of leaves and feeds on the edges. It
becomes yellow or orange prior to pupation and coats the surface to which the
cocoon is fixed with a dense, pinkish carpet of silk. Pupation is usually openly
on bark or a leaf in an ovoid, clay-coloured cocoon with a brown 3mm disc at one
end and a 3.5mm brown ring at the other.
Host-plants noted by Bell are Careya (Barringtoniaceae), Eugenia
(Myrtaceae), Acronychia (Rutaceae), Pongamia (Leguminosae) and
Ricinus (Euphorbiaceae).
A second group of Sundanian species is sister probably to the Sri Lankan
and S. Indian N. argentipuncta Hampson. This differs from the typical
fasciated orange group in having the forewing shaded with pinkish brown. The
synapomorphies uniting these species are suggested to be a small, oblique white
streak at the posterior angle of the forewing cell and a larger than average
brown marginal spot between forewing veins Cula and Culb.
In the male genitalia N. argentipuncta has a setose process
distally on the valve sacculus and densely scobinate lobes laterally on the
juxta. In the Sundanian species the valve is extremely narrow, the saccular
process modified into a ventral lobe and a distal spined band that extends
dorsally and inwardly towards a slender spined process arising basally from the
valve costa. The aedeagus has a subbasally arising setose rod that runs adjacent
to it ventrally to the apex.
The female of N. argentipuncta has a lenticular field of signa as
in N. conspersa but these are fewer, larger; the ductus bursa is very
highly spiralled about eight or ten times over the distal portion. No females of
Sundanian species were available for study; these will be essential to test the
assumption that argentipuncta and the Sundanian species are sister-groups
as the modifications to valve and aedeagus in the latter are so extreme. The
early stages of the latter will also throw light on the problem.
Bell (MS) reared argentipuncta. The larva is a perfect semiovoid,
unadorned, with the subdorsal ridges even, not coming to an angular point. The
body is bright green, the dorsolateral ridges canary yellow, marked on their
inner declivities with seven very dark brown spots on the abdominal segments. On
most segments there are double yellow spots anteriorly and dorsally, and a
lateral row of yellow spots invested each with a dark dot. The venter is white.
The host-plants noted were Macaranga (Euphorbiaceae) and Mangifera (Anacardiaceae);
the larva lives on the undersides of the leaves.
One species of the Sundanian group from Peninsular Malaysia was reared
from a cocoon on coffee and could well have fed on it as a larva. The larva has
been discovered in Sumatra by R. Desmier de Chenon since going to press. It is
ovoid, with strong longitudinal ridges, and will be described in detail by Cock,
Godfray & Holloway (in press). It is described below, together with
Philippines species akin to Bornean taxa. There are four Bornean species known,
and probably more awaiting discovery.
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