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Altha
Walker
Type
species: nivea Walker
Synonym: Belgoraea Walker
(type species: subnotata Walker)
Altha species
have a white ground colour, shaded or fasciated with orange or brown on the
forewing, the veins in the discal area tending to be picked out in white amid
this shading to give a diagnostic reticulate effect. There are prominent dark
dots at one third from the apex on the margins of both wings.
Other diagnostic features for the genus are found in the female
genitalia where secondary ovipositor lobes occur within the major ones (Fig.
106), and setae on the major lobes are apically minutely branched.
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The genus can be divided into two sections, both of which have
representatives in Borneo. The first was reviewed by Holloway (1982a) and
contains species with predominantly white forewings that are relatively
elongate. The female bursa contains a large, single, round scobinate signum.
Within the section the Indian subnotata Walker differs from the wider
ranging nivea group in lacking the asymmetric juxta and narrow saccus; in
this it resembles the second section, but is taken to be sister to the nivea group
on the basis of the facies and bursa characters mentioned.
The second section includes the species adala Moore, lacteola Swinhoe,
rufescens Swinhoe and contaminata Hampson, and is characterised by
broader, shorter forewings more heavily shaded with orange or brown. The signum
in the bursa is reduced to a small patch of scobination.
The species peralbida Swinhoe (India) and alastor Tams (Sulawesi)
need further examination and are probably misplaced. Both lack the diagnostic
secondary ovipositor lobes of Altha and have forewing venation more as in
Althonarosa Kawada. They may be better placed in the latter genus.
The larvae of Altha are oval, convex above, without tubercles.
Moore (1882-4) described a Sri Lankan species attributed to adala, but
probably rufescens Swinhoe, as limaciform, naked, pale green, convex
above, with indistinct dorsal and lateral rows of bluish green dots and
longitudinal lines, and a sublateral row of white dots. The cocoon is whitish,
oval, and the host- plant recorded was Bauhinia (Leguminosae). The larva
of adala Moore is described below.
Two species in the nivea group have been reared. Bell (MS) and
Sevastopulo (1941, 1946) described the larva of subnotata. The very young
larvae are translucent greyish white with a transverse olive brown band
anteriorly, centrally and posteriorly, the central one rather broader than the
others. The shape is perfectly semiovoid, smooth in later instars with segments
obscure, but with a double dorsal series of six transparent glossy humps visible
with a lens which persist until the larva is half grown. The fully grown larva
is pale bluish green, resembling translucent fat, with a narrow white dorsal
band, several wavy lines down the flanks and a yellow sub- lateral stripe
defining the ventral area. The larva is sluggish, living on the undersides of
leaves, eating from the edge. The dull, hard, smooth, white, ovoid cocoon is
found generally between two leaves with a network of transparent substance resembling snail slime stretched in a wall around
it, the leaves superimposed and fixed to the top and bottom of the cocoon.
Host-plants recorded are Bombax (Bombacaceae) Ricinus (Euphorbiaceae),
Shorea (Dipterocarpaceae) Tinospora (Menispermaceae), Musa (Musaceae),
Alseodaphne
(Lauraceae), Mangifera (Anacardiaceae), Zanthoxylum (Rutaceae)
and Terminalia (Combretaceae), but the range is probably much wider.
Sevastopulo (1944) described the early stages of the Himalayan species
associated with melanopsis Strand by Holloway (1982a), the only
reference to the life history of a species in the asymmetric juxta group
located. The body of the larva is oval, highly convex, pale bluish green,
somewhat frosted, with dorsal, two subdorsal and two sublateral rows of pale
yellow specks, those of the inner subdorsal rows alternating with those of the
outer dorsal rows. The venter is yellowish green. The cocoon is oval, chalky
white, spun amongst leaves, concealed under a web of slight, frothing silk. The
host-plant is (Thea) Camellia sinensis (Theaceae; tea).
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