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Bendib & Minet (1999)
considered this tribe was most reliably defined on the loss of discrete D1
verrucae on larval abdominal segments 1-8. They also suggested two characters of
the adult were apomorphic: a band of fine, close-set strigae laterally on the
metepisternum, distinct from the microtymbals (also, probably homoplasiously, in
a few Cisthenini); lack of an opening on the posterior wall of the tergal rim
(also seen developed in parallel in the Lithosiini, some Cisthenini and a few
Endrosini).
The
forewing veins are often all present (reduced in the ‘translucent’ group
discussed below), and there is multiple fasciation, sometimes broken up into
dots or striae. Discal and other dots in the cell are often present. In most
genera (Cyana Walker is an exception with reductions) the hindwing
venation has Rs+M1 stalked or fused, and the four more posterior veins are
present and separate.
Bendib
& Minet recognised two subgroups within this tribe, both of which are
represented in Borneo. Cyana and Paidia Hübner have CuA1 and M3
stalked or coincident (Fig 10i), a projecting lobe near the base of R2 under the
male forewing, and fusion of D and SD2 into a single verruca on T2 and T3 of the
larva. The second subgroup is much larger and is defined by reduction of the L
setae to a single verruca (L2) between the spiracle of the proleg on A3 to A6.
This includes two major groupings of genera: a complex that includes Thumatha
Walker, Asura Walker and allies and Miltochrista Hübner (Thumatha
to Eutane Walker in the sequence following) that may be defined by
possession in the larva on segments T3 and A7 of a large eversible gland between
verrucae D and SD; a group of rather delicate, translucent species usually with
V-shaped wing scales (Schistophleps Hampson to Nudaria Haworth in
the sequence following) that often also have an elongate antennal scape and
reduction of the forewing venation in the radial sector that includes only
bifurcate branching systems but sometimes two of these (e.g. Schistophleps). Many
of the Thumatha group genera have a pair of coremata in the male eighth
abdominal segment (e.g. Figs 268,270,272), and the valve of the male genitalia
frequently has a process arising from near the centre of the costa. They also
may have enlarged paratergal sclerites in the male genitalia as in the
Cisthenini, though in a less extreme form. The Thumatha sequence
include numerous taxa that were referred to Asura and Miltochrista by
authors from Hampson (1900) to Bendib & Minet (1999); an attempt has been
made here to find more satisfactory generic concepts for these taxa.
Fig 10i: Cyana pudens Walker
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The
adult resting posture in the tribe varies from tectiform to one converging on
that defining the Lithosiini (Cyana).
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