View Image Gallery of Family Bombycidae

Gunda Walker

Type species: ochracea Walker.
Synonyms: Norasuma Moore (type species javanica Moore, Java); Aristhala Moore (type species hainana Moore, Hainan); Clenora Swinhoe (type species engonata Swinhoe, S. India) syn. n.; Hanisa Moore (type species subnotata Walker, Singapore) syn. n.

The wing venation of this genus is as in the Ocinara group (Fig 4) , but the forewing is usually strongly falcate, often also angled obtusely at the centre of the margin. The coloration is rich brown to yellowish brown and there is strong sexual dimorphism, the females usually larger, paler and less heavily marked than the males.

Figure 4. Venation in the two lineages of the Bombycidae: left, Mustilia dierli; right, Ocinara albiceps.

The male abdomen has the eighth sternite modified into a symmetrical pair of arms, often with flanges or spurs on the anterior surface. The valves are basally globose, tapering apically into a curved, sclerotised process that is excavate apically in most species; there is sometimes a small spur or process at the apex of the sacculus. The saccus is relatively short. The uncus is slender, bifid, and the genitalia as a whole are rather elongate and narrow. All the type species of the genus-group names listed above have these genitalic features as well as marked sexual dimorphism and are therefore brought into synonymy.

The female genitalia have small dorsal accessory lobes to the ovipositor lobes, most strongly developed in G. subnotata (Fig. 102), but also seen in the Ocinara group of genera. The ductus and bursa are weak, arising from the thin (very thin in subnotata) ring of the eighth segment. A weakly sclerotised hornlike structure arises centrally from the posterior membrane of the eighth tergite in G. ochracea (Fig. 103).

Bell (MS) described the early stages of G. engonata Swinhoe, the type species of Clenora, and a species from southern India related to G. javanica. The eggs of the latter are thick, oval discs, the ends broadly truncated, and are laid on top of each other and side by side like a brick wall. The young larva has very small, hairlike secondary setae. There is a horn on segment A8, thick, tapering, slightly curved, extrusible with a white apiculus. The colour is a greenish rusty brown with a white saddle over the central segments. The thorax is somewhat swollen anteriorly, and there are transverse dorsal swellings on A2 and A5 (see members of Ocinara group also). The swellings and horn are tinged orange. The pale saddle is yellower and marked blackish in later instars. The larvae rest in a twig-mimic posture, the body anterior to the second proleg held away from the stem at an angle. Later instars are ochreous white or grey, marked with black, particularly in a patch between segments A3 and A4. The ridges on A2 and A5 and the horn remain orange. The larvae are gregarious in the first three instars, but may separate in the penultimate instar. Pupation is in the fold of a leaf or a bark crevice in an ovoid silk cocoon with a loose outer cover, white or cream-coloured. The larva of G. engonata is similar in shape but lighter, more lichen-like in colouring, and the transverse ridge of A2 and A5 is divided into subdorsal and dorsolateral tubercles. Both species were reared on Ficus (Moraceae).

The Javan G. proxima Roepke (1924) (? also in Peninsular Malaysia and Timor) lays its flattened, black, glossy disc-like eggs (with a ridge round the upper rim) in untidy stacks on the underside of a Ficus leaf. Roepke illustrated the larva as having the thoracic segments strongly swollen as in Bombyx, the body thence tapering gently to the rear, with a strong upcurved horn on A8.

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