View Image Gallery of Family Limacodidae

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.

Narosa concinna

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.

<<Back >>Forward <<Return to Contents page

Copyright Southdene Sdn. Bhd. All rights reserved.