Type species: guttiventris Walker, a junior synonym of transversa
Nachaba Walker is the older generic name associated with this group (type
species transversa Walker) but is a junior homonym (Nye 1975).
The species are mainly small with male antennal pectinations typical of
the subfamily but not as highly developed as in some other genera. The forewing
margins are not angled but gently curved. The forewing pattern consists of a
number of dark, fine almost straight fasciae, the postmedial and antemedial
being the most intense. Any species without this typical pattern (e.g. several
African taxa such as polymorpha Hampson and lichenosa Hampson)
currently included in Chlumetia (e.g. by Gaede 1935) will probably prove
to belong to Targalla; they have filiform antennae in the male and facies
characters consistent with such a placement.
In the male the eighth abdominal sternite has the coremata borne on
either side of a complex triangular structure that terminates centrally in two
long curved spines, probably modified setae (Fig. 102a); the coremata are only
slightly eversible, more pad-like, with a dense array of hair-like setae. The
valves of the male genitalia are simple, usually short and rounded; the saccus
is long and slender, in most cases extremely so; the aedeagus vesica lacks
In the female genitalia the bursa usually has two typical signa and is
associated with a globular appendix bursae that is finely scobinate. The
development of bursa and appendix relative to each other varies from species to
species, as does their position of union. In one species the signa become
elongate; in others the vaginal lamellae become modified, ‘pinched in’
somewhat, or (e.g. in transversa) are developed into lateral scobinate
lobes. The apophyses of segment 8 are generally present as short, broad flanges.
There are several species or species groups that extend throughout the
Indo-Australian tropics. Larvae of some of them (records are usually attributed
to transversa) are pests of mango, boring in the young shoots. Because of
their economic significance an attempt is made here to clarify the taxonomy of
the group as well as to illustrate the several species found in Borneo.
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