Phlebohecta viduata Jordan

Phlebohecta viduata Jordan, 1912, Novit. zool., 19: 149.

Diagnosis

The wings are very narrow, and the general colour is black. There is a yellowish patch at the base of the forewing on the tegulae of the thorax, and narrow transverse bands of the same colour at the posterior of the thorax and (two to three) at the centre of the abdomen. The distal margins of the wings are white. There is a conspicuous white patch on each wing, ovate, in the discal area of the forewing; triangular, at one third in the centre of the hindwing.

Taxonomic note

“P.” lypusa Jordan from the Batoe Is., Singapore and Peninsular Malaysia is similar; the species lacks the pale thoracic and abdominal markings of viduata. Yen et al. (2005) indicated that these species should be transferred to a new genus, together with “Trypanophora” producens Walker. The male abdomen of viduata has the eighth tergite reduced, but the sternite is enlarged, pincer-like as illustrated. The genitalia have the uncus shallow, vestigial, but there is a strong, triangular saccus. The valves are somewhat quadrilateral, with a more strongly sclerotised ventral margin. The aedeagus is sinuous, with a slight subbasal projection as illustrated.

Geographical range

Borneo.

Habitat preference

The species is frequent in lowland forest of various types, and has been recorded singly at 1618m on Bukit Retak in Brunei.

Biology.

The larva of a species, probably lypusa, in that it lacks a pale yellow posterior line and pale tegulae on the thorax, has been reared to adulthood in Singapore (T.M. Leong, pers. comm.). A photograph of the larva shows it to have subdorsal, dorsolateral and subspiraocular rows of knob-like scoli on each segment, these bearing the primary setae and, on the subspiracular ones, a fine pubescence. These most ventral scoli are longer at the thoraco-abdominal junction, reducing in size anteriorly and posteriorly, giving this region an angular appearance seen from above. A similar elongation of these scoli is seen at the posterior end. The body is a rich, glistening brown that is more honey-coloured over the posterior half. There is a dorsal black dash longitudinally on each segment amid a more general dark marbling.

The cocoon of dense greyish silk is spun in a longitudinal fold of the leaf along a rib, adhering closely to it.

The host plant was Melastoma malabathricum (Melastomataceae).

Genitalia: