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Sphetta
Walker
Type
species: apicalis Walker (Indian Subregion, Java, Bali).
The
species have rather long, narrow forewings with a large cream-coloured,
lens-shaped patch at the costa over the distal half; this patch grades into
brown basad and inserts a triangular tooth into the otherwise blackish cellular
area. The rest of the insect is dark brown or blackish. The hindwings are
rounded, and the abdomen extends well beyond their extremity. On the forewing
below there is a long subbasal flap of broad scales directed anteriorly from CuA.
The antennae are finely ciliate in the male; females are not known.
General
features of the male genitalia have been described in the previous section.
There is an X-like structure above the anellus formed probably from the
transtillae. The valves have a band of sclerotisation running from the sacculus
to expand into a disc subapically that is edged with spines.
The
mature larva of the type species was described by Bell (MS). It is cylindrical,
slightly broader centrally. A8 is broadened by four conical hair tubercles in a
transverse row, subdorsal and dorsolateral pairs. There are similar large
dorsolateral tubercles on all segments except Ti but the subdorsals are smaller.
A10 has the tubercles flatter, the subdorsals fronted by humps bearing black
bristles. There are secondary setae elsewhere also: The head is semi-elliptical,
narrowing upwards, slightly bibbed. The spiracles are jet black, very large, the
rims coarse and shining. Ventrally the larva is glassy, soiled whitish. There is
a broad (1mm) pale yellow band above this running from T1 to the anal clasper.
Above this the whole dorsum is washed out lilac or violet, tinged pink, with a
longitudinal paler band passing through the dorsolaterals and another through
the subdorsals. Laterally above the yellow band is a fuscous suffusion. The
tubercles are mainly orange, some black-tipped (posterior subdorsals). Smaller
supraspiracular tubercles are black. Many of the thoracic hairs (T1 and T2) are
white or have white bases. Sevastopulo (1939) referred to white subdorsal lines
that are posteriorly slightly convergent, forming a V, on each abdominal
segment. Moore (1882-3) also described and illustrated the larva.
Early
instars are less strongly coloured, more translucent. The egg is a depressed
sphere with a finely reticulate surface, white, with a circular brown patch at
the top, where it is slightly concave. The eggs are laid singly on the
host-plant on the underside of a leaf. Bell considered them notodont like.
The
mature larva behaves in notodontid fashion, eating the leaf from tip to base,
straight across from edge to midrib, from a position along the midrib. Pupation
is in a cell of leaves held together with silk.
The
host-plants noted by Bell were Pongamia, Derris (Leguminosae) and Sapindus
(Sapindaceae). Moore (1882-3) noted Diospyros (Ebenaceae) and Nephelium
(Anacardiaceae) as host-plants.
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