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Biston Leach
Type species: prodromaria Denis & Schiffermüller = strataria
Hufnagel, Palaearctic.
Synonyms: Dasyphara Billberg, Pachys Hübner,
Amphidasis Treitschke (type species prodromaria); Eubyja Hübner
(type species betularia Linnaeus, Palaearctic); Buzura Walker
(type species multipunctaria Walker = suppressaria Guenée,
India); Eubyjodonta Warren (type species falcata Warren, N.E.
Himalaya); Blepharoctenia Warren (type species bengaliaria Guenée,
India).
Inoue (1982, 1985) indicated that the large
yellow-tinged Oriental Buzura Walker species should be included within a
broadened concept of Biston Leach. He based this decision on external and
genitalic characters shared between Palaearctic and Oriental taxa of the two
genera.
Rindge (1985) attempted to define the tribe Bistonini on apomorphic
characters. These should obviously be manifest in Biston, the type genus,
if in none other. In fact, the table given by Rindge only indicates Biston to
possess two: labial palps not extending beyond eyes; eyes hairy. Other
characters generally shared amongst the other N. American Bistonini recognised
by Rindge include female brachyptery, reduction of female tympanal organs and a
vestigial or absent tongue. These features are probably homoplasious features
associated with flightlessness in high latitude moth taxa (Sattler, 1991). Few
of the taxa in Inoue's broader concept of Biston have hairy eyes: in the
type species of Biston, strataria, the eyes are smooth.
The species are robust, the facies typically boarmiine with an anteriorly
angled postmedial, and often a subsidiary angle subdorsally. Many species have a
band of brown, green or yellow associated with the post- and antemedial fasciae,
distal to the former, basal to the latter. The male antennae are bipectinate,
those of the female being filiform. There is no fovea on the male forewing.
Females tend to be larger and less heavily marked than males. The male abdomen
lacks a setal comb on sternite 3. The genitalia have the uncus apically bifid,
the gnathus robust, extensively rugose. The juxta is elongate, apically free,
acute, often extending to the dorsal margin of the tegumen. An extended juxta of
this nature is seen also in Amraica Moore and Cusiala Moore,
discussed below. The valves are typical of the boarmiine ground plan with a
strong cucullus. There is no ornamentation on the costa or sacculus. The
aedeagus is usually apically sclerotised, fluted, sometimes scobinate, the
vesica simple, reflexed, scobinate.
The female genitalia have the ovipositor and apodemes elongate,
extensile as in the next three genera, Cleora Curtis and Ectropis Hübner.
The neck of the bursa is long, the signum somewhat reduced, transverse, dentate.
The larva is generally twig-like with the characteristic 45 degree
resting posture and an obtusely cleft head. Most species are highly polyphagous
defoliators. The type species of Buzura has been recorded as feeding on
the following plant taxa (Singh, 1953; Browne, 1968; Bell, MS;
unpublished IIE records): Bombax (Bombacaceae); Aleurites, Mallotus,
Phyllanthus (Euphorbiaceae); Acacia, Cassia, Dalbergia, Gliricidia (Leguminosae);
Lagerstroemia (Lythraceae); Cedrela (Meliaceae); Eugenia (Myrtaceae);
Citrus (Rutaceae); Camellia (Theaceae); Grewia (Tiliaceae).
All three Bornean species belong to section Buzura. This extends
east to the Moluccas. The island does not support a representative of the
large-sized regalis group, though this occurs in the mountains of
Peninsular Malaysia (B. giganteus Inoue), Java (B. pelidna Prout)
and Sulawesi (B. subregalis Inoue).
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