Europlema Gen. n.
Type species: desistaria Walker.
The majority of species in this genus has characteristic facies.
The forewings have mottled or striate brown, grey and black markings on
a white ground. The latter extends more or less unmarked along the dorsum. The
submarginal row of dark, lunulate marks is more complete than in other genera,
often forming a clear arc or semicircle. The typically two-tailed hindwing has
the costal zone broadly white, separated from the rather striate, rusty brown
posterior two thirds by an irregularly crenulate boundary. Two fine, diverging,
rusty fasciae cross this dorsal white area centrally.
The male antennae are lamellate. In the forewing venation, R2 arises
from R3+4. In the hindwing, M2 is weak or absent. The hindwing has only one anal
vein, and the origin of CuA2 is subbasal and somewhat asymptotic to the cell.
The male genitalia are also characteristic. The uncus is triangular,
folded longitudinally in a roof-like manner, ventrally setose. The gnathus is
present, divided into two curved blades. The valves are somewhat triangular,
with a distinctive, slender process arising from the base ventrally. These
processes align either side of the aedeagus naturally, but are usually deflected
ventrally when a slide-mount is prepared. The ductus ejaculatorius of the
aedeagus is often spiralled.
The female has the ductus seminalis similarly spiralled, joining the
bursa basally, often with some sclerotisation at the junction. The ductus is
short. The bursa contains one large signum, sometimes opposed by a smaller one.
In addition to the Bornean species treated below, the genus also
includes: E. conchiferata Moore stat. rev., comb. n. (= semifulva Warren
syn. n.; Sri Lanka, India); E. melanosticta de Joannis comb. n.
(Mauritius); E. quadripunctata Wileman comb. n. (Taiwan); E. irrorata
comb. n. (Indian Subregion); E. nigropustulata Warren comb. n. (Obi);
vacuata Warren comb. n. (Solomons). The first listed is removed from
synonymy with desistaria (as listed by Nielsen, Edwards & Rangsi
(1996)), as are several other Bornean taxa.
Bell (MS), Bigger (1988) and Chen (1997) recorded the biology of members
of the desistaria complex, the host-plant in each case being Premna (Verbenaceae).
Bigger described his caterpillar as green, slug-like. Bell stated that the larva
is spindle-shaped, fat, shining, with a small head and prothorax. It is
grass-green with a darker, dorsal, pulsating line and a subcutaneous, whitish
subspiracular line. The pupal cremaster has eight rather stout, hooked shafts.
Pupation is in a slight cocoon in the fold of a leaf or similar place. The pupa
is attached by its cremaster. Chey (1994) recorded members of the genus
significantly more commonly from Gmelina arborea (Verbenaceae)
plantations than from plantations of other species, so this may be an
alternative host. At rest, forewings and hindwings are folded in a Z-shaped way
in cross-section (Chen, 1997).
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