The bulk of this tribe is made up of the genus Idaea Treitschke,
of which the type genus, Sterrha Hübner, is a synonym. Most species are
similar in appearance to some Scopula, with finely fasciated fawn,
reddish fawn or greyish wings. The postmedials rarely have significant
displacement basad at vein M2.
In the male, the hind-legs are often distinctly reduced, with a massive
scent-pencil obscuring most of the leg. The antennae are usually strongly
ciliate or serrate, compared to those of the female which are filiform. At the
base of the abdomen the second sternite is variably modified, sometimes with a
strong rugosity, occasionally with a definite pouch as in the Scopulini. The
eighth segment is sometimes enlarged but lacks distal processes. The genitalia
have a small uncus and gnathus of the ground plan geometrid type. There are no
socii. The valves are long, narrow, usually strap-like. The tegumen is usually
much longer than the vinculum, the latter often having a small saccus. Coremata
are at the valve bases in Lophophleps Hampson, the second of the two
Bornean genera, and in some Idaea species. The aedeagus is usually
relatively large, the vesica containing one to several moderate to large cornuti.
The bursa in the female is often generally spined as in many Larentiinae
though sometimes the spines are restricted to a few bands. The ovipositor lobes
appear to offer a tribal autapomorphy: they are bilobed into a rounded dorsal
portion and a shorter, narrower ventral one, seen most clearly in Fig 237.
As with Scopula, the genus Idaea contains many species
with herbaceous-feeding larvae, but these sometimes show a preference for dead
foliage (Allan, 1949; Sugi, 1987). Sugi noted that Idaea larvae are
characterised by apically clubbed or spatulate body setae: they are shorter,
stouter, generally darker and rougher in appearance than those of Scopula. The
only host record located for Lophophleps is for the type species, reared
from the fruits of Shorea macroptera (Dipterocarpaceae) in Peninsular
Malaysia by Dr R. Toy (pers. comm.).
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