Ptisciana seminivea Walker
Ptisciana seminivea Walker, 1865, List Specimens lepid. Insects Colln Br.
Mus., 33: 912.
Symitha lilacina Moore, 1888, Descr.
Indian lepid. Insects Colln W.S. Atkinson: 289.
Diagnosis. The forewings are rather paddle-shaped, a distinctive silvery
grey with irregularly paler fasciation and, along the costa only, much darker
Geographical range. Oriental tropics from the Indian Subregion to Sundaland,
the Philippines and Sulawesi.
Habitat preference. The species is found widely but never commonly in
various lowland habitat types, mostly forested, up to 1000m. Chey (1994) found
the species to be frequent in secondary and plantation forests.
Biology. Bell (MS) reared the species in India. The larva is cylindrical,
with segments well defined by constrictions. There are long primary setae on
prominent conical or spine-like tubercles. All prolegs are present. The head is
trapezoid, light yellowish, with white setae. The body surface is shiny and
glossy, light grass green with a lateral, spiracular faint yellow spot on the
anterior margin of each segment. The dorsolateral tubercles are bright pale
yellow, those of T3, A2, A4, A6 and A8 connected across the dorsum by
semicircles of the same colour.
Pupation is in a long, oval cocoon, more or less pointed at each end, attached
to a branch or twig and incorporating particles of bark. The pupa is dorsolaterally flattened, squarish anteriorly, a depressed semiovoid. The
abdomen narrows sharply over A8 to A10, the latter conical with a dorsal beaded
ridge over the anterior margin. The pupa shivers in the cocoon when alarmed,
producing a rustling noise.
The young larvae live on the undersides of tender leaves of the host-plant,
eating only the cuticle when freshly hatched, then holes in the leaf, only later
feeding from the edge. Parasitism by Hymenoptera and Diptera is frequent.
The host-plant is Macaranga (Euphorbiaceae).
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