The bluish to purplish metallic reflections of the forewing combined with the triangular
silver mark on the costa serve to distinguish species of this genus externally.
In the male genitalia, the elongate anterior extension of the vinculum, the
setose lobes appressed to the tegumen, the reduction of the gnathos, and the apical
processes of the aedeagus are together diagnostic. The weakly sclerotized bursa
and lobed bases of the anterior apophyses in the female genitalia are
distinctive.

Synapomorphies:

(1) Forewing with silver streak from costa and apical suffusion of metallic
scales.

(2) Gnathos strongly reduced or lost.

(3) Tegumen with appressed setose lobes (possibly representing a modified
uncus).

(4) Anterior extension of vinculum elongate.

(5) Pectinifer strongly reduced.

(6) Transverse bar of transtilla broken in middle.

(7) Aedeagus with one ventral and one dorsal process.

(8) Apophyses anteriores with expanded bases.

(9) Corpus bursae with diverticulum. (Not known with certainty for R.
sapphiripes.)

Adults. Head capsule: Labial palpus 3-segmented;
galea short, not extending beyond labial palpus; maxillary palpus 5-segmented,
ratio of segments from base approximately 0.2: 0.4: 0.7: 1.6: 1; interocular
index (Davis 1975) 0.8. Collar consisting of piliform scales. Thorax and
forewing fuscous with strong bluish or purplish reflections; forewing costa
with a triangular silver mark 2 3 along its length; apex
of forewing with suffusion of silver or bluish metallic
scales. Hindwing grayish, without specialized scales; 6–8 costal bristles in
male. Underside: forewing without subdorsal retinaculum. Wing venation:
forewing with R2+3 absent, R4 stalked with R5, Cu separate from base of wing, very
long, 1+2A not thickened and running obliquely from base of
wing to meet dorsum well before tornus; hindwing with trunk of Rs+M deflected towards costa. Abdomen without specialized scales; S2a (van Nieukerken
1986) as in Figure 7 (Hoare 2000), approximately pentagonal, with transverse
rows of fine spines medially; T2 with continuous anterior sclerotization and 3–4
fenestrae on each side. Legs: fore- and mid-legs unremarkable; hind-tibia with
proximal pair of spurs inserted well above middle; inner proximal spur very long,
more than half length of tibia.

Male genitalia. Vinculum with long
subrectangular anterior projection. Lateral arms of vinculum fused with
tegumen, but not forming complete ring. Tegumen simple, band-like,
antero-lateral corners more or less produced into lobes (possibly representing reduced
uncus), each bearing a small number of setae. Gnathos absent or represented by
2 weak lateral sclerites. Valva with rounded medial lobe and exterior digitate
process, incurved and reaching to tegumen or just beyond; pectinifer reduced to
narrow thickening along rounded apex of process. Transverse bar of transtilla present,
interrupted in middle. Aedeagus with ventral and dorsal apical processes. Vesica
with 1 to 17 spine-like cornuti; base of ejaculatory duct with pair of
lip-like, faintly striate thickenings.

Female genitalia. S8 bluntly rounded.
Anterior apophyses with broad lobed bases. Accessory sac somewhat developed.
Corpus bursae elongate, with diverticulum, weakly sclerotized, without
pectinations or signa.

Larva. Head: antenna 3-segmented, segments 2
and 3 each with 1 sensillum basiconicum and 1 sensillum chaeticum; labial
palpus 3-segmented; stipes with 2 setae; frontoclypeus approximately square;
anterior tentorial arms approximately 2 times as long as posterior; posterior
lobes continuously sclerotized caudally. Thorax: prothoracic sternite (Fig. 34)
subrectangular, more strongly sclerotized posteriorly; dorsal sclerites (Fig.
35) elongate, with small expansion on inner edge towards distal end; T1 with 13
pairs of setae; T2 with 11 pairs (2 D setae present; 3 setae ventral to SV1;
SD2, L2 and L3 minute); T3 with 9 pairs (1 D seta and 2 L setae present). Abdomen:
A1–8 with 6 pairs of setae; A9 with 3 pairs; A10 with 3 or 4 pairs; anal rods
apically pointed. T2–3 and A1–7 each with broad central band of relatively long
spines; A8–9 with spines confined to venter and dorsum; T1 and A10 not spinose.

Cocoon. Reddish brown, flattened.

Pupa. Head : Clypeus squarish; frons with a
pair of conspicuous setae posteriorly; labial palpi distinctly longer than
maxillae. Eclosion more or less dorsal, so that suture between eyecaps and
frons remains largely intact ventrally. Abdominal segments 2–8 each with 3–4
rows of spines on dorsum and a prominent pair of dorsal setae.

Host plants: Cunoniaceae, Eucryphiaceae and Elaeocarpaceae.

Roscidotoga is only known from eastern Australia, with three
species in south-eastern Queensland, two species in south-eastern New South
Wales and one species in Tasmania.

All species live in subtropic to temperate rainforests

Roscidotoga is considered to be sister taxon of Pectinivalva