Fibiger, Fibiger, 2007

Fibiger, Michael, 2007, Revision of the Micronoctuidae (Lepidoptera: Noctuoidea). Part 1, Taxonomy of the Pollexinae, Zootaxa 1567 (1), pp. 1-116 : 32

GENUS DISCA Fibiger , new genus

Type-species Disca arborita Fibiger, new species.

Diagnosis. Generally as described under the subfamily. Further characters are listed here; autapomophic character are shown as (apo.).

Imago (external).

Head, patagia, and costa of basal area: grey to light brown.

Wings: broad (apo.).

Wingspan: 11–13 mm (6 species), on average smaller than for Tolpia and larger than for Pollex .

Hindwing: concavity medially on termen is much weaker than for Tolpia and Pollex (apo.).

Forewing costa: black at base (synapomorphy shared with Tolpia ).

Transverse lines: present, light brown; each line represented on costa by a black dot.

Fringes: length of scales in three levels, appearing as three lines.

Reniform: narrow, well marked, ovoid, outlined in dark brown (apo.).

Hindlegs: scent brushes lost from hindlegs of male, unlike those of all Tolpia and some Pollex

(apo.).

Male genitalia.

Ampulla: large, round to slightly ovoid (apo.).

Pollex : forms sharp angle on ventral margin of valve.

Digitus: short, prominent, asymmetrical, bent 90? medially.

Juxta: totally fused with anellus, higher than wide.

Phallus: long, broadly V-shaped (a 95–100? bend) at 2/3 from base

Female genitalia.

Abdominal segments 7 and 8: heavily sclerotised, fused Together.

Ovipositor: quadrangular.

Antrum: cone-like, smaller and shorter in Tolpia .

Corpus bursae: globular, with typical Micronoctuidae characteristics.

Differential diagnosis. In Disca the reniform is narrowly ovoid, well marked, and outlined in dark brown, whereas in Tolpia species the reniform is represented by an elongated black to brown streak, and in Pollex species the reniform is broader and usually has a bright yellow to greyish-white centre. The male genitalia of Disca has a smoothly rounded to ovoid ampulla and a prominent, short digitus. In Tolpia , by contrast, the ampulla is bent (ranging from narrow to broad) and the digitus is very long and tapered to the tip; in Pollex the ampulla of is long and narrow, club-like to stick-like and the digitus is long and subapically broad. The pollex of Disca is a sharp quadrangular hump; whereas that of Tolpia is short, usually thumb-like, and that of Pollex is extremely long, most often finger-like. The phallus of Disca has a sharp medial bent before curling a litte clock-wise; that of Tolpia is very long, with several bends, prominently coiling; and that of Pollex is usually short or wide and evenly curved in a broad sicle shape.

Distribution. Mainly in the Oriental and northern Indo-Australian Regions.