Type species: fuscescens Walker,
Synonyms: Dictenus Butler
(type inconstans Butler, Malawi); Nudoridia Hampson (type muscula
Staudinger, Ussuri); Pelobrochis Lucas (type rava Lucas,
This genus contains a number
of small, dull, paleish brown species with rather rounded wings. They are found
throughout the Old World into temperate latitudes. The male antennae are
bipectinate. All veins are present, with R1 anastomosing with Sc and ((R3, R4)
R5) forming the radial sector branching system in the forewing, and Rs stalked
with M1 and M3 with CuA1 in the hindwing (Fig 5h). The forewing
pattern consists of a discal spot flanked by obscure, irregular fasciae; there
is usually a submarginal row of dark streaks on the veins. The hindwings are
usually paler and may also have a discal spot or lunule.
Fig 5h: Thumatha fuscescens Walker
The male genitalia are
characteristic with a short, bulbous, dorsally ridged uncus, a broad saccus, and
valves that are ovate with an excavation in the distal part of the ventral
margin leading into the thornlike terminal process of the sacculus, also
marginal; there is a ventrally directed triangular flap arising subcostally on
the interior face of the valve near its centre. The aedeagus vesica contains
The female genitalia have a
very broad, rather bulbous, sclerotised ductus, and a flimsy, spherical bursa (fuscescens).
The bursa may contain a scobinate signum (senex Hübner).
The larva of the European
species, senex, was described by de Worms (1979). The head is shining
black, the body a deep waxy red with dense tufts of setae on verrucae. The setae
are black, slightly plumose, or pale brown with black tips. Pupation is in a
thick brownish cocoon of silk incorporating larval hairs.
The larva feeds on lichens
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