Episothalma Swinhoe, 1893

Xue, Dayong, Wang, Xuejian & Han, Hongxiang, 2009, A revision of Episothalma Swinhoe, 1893, with descriptions of two new species and one new genus (Lepidoptera, Geometridae, Geometrinae), Zootaxa 2033, pp. 12-25 : 14

Episothalma Swinhoe, 1893

Episothalma Swinhoe, 1893 a, Ann. Mag. Nat. Hist. (6) 12: 149. Type species: Thalassodes sisunaga Walker, 1861 , by original designation. [ INDIA]: Hindostan.

Episthophthalma Hampson, 1895 , Fauna Br. India (Moths) 3: 483. [Emendation of Episothalma .]

Redescription. Head: Antenna ciliate in male, filiform in female. Frons moderately protruding, smoothscaled. Labial palpus short, third segment in female elongate. Thorax: Hind tibia with one pair of terminal spurs in male and two pairs of spurs in female. Wing pattern: Outer margin of both wings wavy, lightly concave under forewing apex and deeply concave between M1 and M3 on hind wing; inner margin on hind wing elongate. Transverse lines on both wings distinct or indistinct; forewing with antemedial line slightly wavy; both wings with postmedial lines slightly dentate; discal spots dark brown or black dot on both sides. Both wings with ventral side much paler than dorsum; postmedial line distinct. Venation: Frenulum developed. Forewing: Vein R1 free; R2-5 and M1 diverging from the anterior angle of cell; R2 diverging before R5; M3 and CuA1 from the posterior angle of cell. Hind wing: Rs longly stalked with M1; M3 and CuA1 stalked or both from the posterior angle of cell; 3A absent. Abdomen: Dorsal crests present. Sternite 3 in male without setal patch. Male genitalia: Uncus developed, tapered or blunt at apex. Socii weak, usually shorter than uncus. Gnathos with lateral arms not joined at middle. Valva with apex rounded, setose; a longitudinal, irregularly wrinkled ridge with dense hair present in central part; a tapered, fairly sclerotized fold or hook present in the center, posterior to which there is a small lobe or a large dentate process. Transtilla a large sclerotized plate. Juxta a slightly to moderately sclerotized plate, posterior margin arched to reversed U-shape. Saccus not protruding, vinculum developed. Coremata fairly developed. Aedeagus moderately slender, broad and sclerotized posteriorly, manica often with sclerotized process, sometimes vesica sclerotized and wrinkled. Female genitalia: Apophyses anteriores very short. Lamella postvaginalis a small and rounded plate. Ductus bursae broad and fairly long, sclerotized. Corpus bursae moderately large, membranous, wrinkled, with a bicornute signum.

Diagnosis. The genus Episothalma looks superficially similar to Euxena Warren, 1896 , a member of the Aracimini, on wing patterns, but can be differentiated easily on external features. The main differences are as follows: Episothalma has a much smaller discal spot on the dorsal side and paler markings on the ventral side, but Euxena has a much larger discal spot on the dorsal side and stronger markings on the ventral side; the male hind tibia has only one pair of terminal spurs in Episothalma , while there are two pairs of spurs in Euxena ; the paired setal patches of sternite 3 in the male are absent in Episothalma but present in Euxena . As a member of the Hemitheini , Episothalma is different from Euxena in the male genitalia: for example, the socii of Euxena are triangular and broader, while those of Episothalma are tapering or with small lobes proximately; coremata are developed in Episothalma but absent in Euxena . In the male genitalia, Episothalma is distinctive in the tribe Hemitheini in having a tapered, fairly sclerotized fold or hook in the center of the valva.

Distribution. Oriental region, including China, Vietnam, India, Myanmar, Nepal, Thailand, Malaysia (West and East), Indonesia (Java, Sumatra, Kalimantan).