Thalassodes Guenée, 1858

Han, Hongxiang & Xue, Dayong, 2011, Thalassodes and related taxa of emerald moths in China (Geometridae, Geometrinae), Zootaxa 3019, pp. 26-50 : 27-28

Thalassodes Guenée, 1858

Thalassodes Guenée, 1858 , in Boisduval & Guenée, Hist. nat . Insectes (Spec. gén. Lépid.), 9: 359. Type species: Thalassodes pilaria Guenée, 1858 , by subsequent designation by Moore, 1887. SOCIETY ISLANDS: Tahiti Island.

Description. Head: Antenna of male bipectinate, adpressed, tapering and filiform at tip, filiform in female. Frons slightly projecting, rough-scaled. Labial palpus weak, third segment in female slightly elongate. Thorax: Hind tibia usually dilated in male, with hair-pencil and terminal extension; two pairs of spurs in both sexes. Wing pattern: Outer margin of both fore- and hind wings usually smooth, and usually distinctly angled at middle of hind wing, occasionally serrate on both wings (e.g. T. zebrata Warren, 1906 ( Papua New Guinea)); inner margin of hind wing elongate. Apex of forewing pointed (especially so in T. acutipennis Prout, 1916b ( Caroline Islands)) to blunt, that of hind wing protruding or rounded. Wings bluish green, semitransparent, diffused with whitish to pale green streaks. Forewing with costa yellowish or whitish; antemedial and postmedial lines indistinct, linear, slightly dentate or sinuous, the latter almost perpendicular to inner margin. Hind wing with postmedial line straight or sinuous at upper half, bending inwards at CuA1, then wavy to inner margin. Submarginal line usually absent. Terminal line appearing as small dots on vein ends if present. Fringes yellowish white. Venter pale bluish green, streaks on dorsum discernible. Frenulum present. Venation: Discal cell shorter than 1/2 length of wings. Forewing with R1 diverging from upper angle of cell or proximally, close to or connected with Sc; R2–5 shortly stalked with M1, M3 shortly stalked with CuA1. Hind wing with Rs stalked with M1, M3 stalked with CuA1; discocellulars oblique; 3A absent. Abdomen: Third sternite of male abdomen with pair of setal patches; eighth segment unmodified or slightly modified. Male genitalia: Uncus, socii slender, tapering, of similar length. Gnathos with median process long, narrow, pointed. Valva usually with pointed to tongue-like process (here named ‘valva basal process’), often spined or scobinate, arising from near base of transtilla and sometimes near base of sacculus; harpe often present, appearing as an oblique sclerotized band at the centre of the valva, usually forming small spur near the ventral margin of the valva, sometimes harpe bearing one to two, small to large processes; Sacculus expanded, margin often scobinate. Saccus broad, sometimes with a small mesal, cephalic process. Coremata usually present. Aedeagus slender; often with blunt cornutus on vesica; sometimes coecum penis considerably long, narrow. Female genitalia: Sterigma sclerotized. Ductus bursae short to long. Corpus bursae small, spherical to oval, with a bicornute signum.

Diagnosis. On wing pattern, typical Thalassodes are very close to Pelagodes , except that the hind wing outer margin is more strongly angled in Thalassodes . The hair-pencil and the terminal extension on the hind tibia in Thalassodes , which are characteristic for Thalassodes , are absent in Pelagodes , Orothalassodes and Remiformvalva. In the male genitalia, Thalassodes has many characteristic features, such as: well-developed valva basal process, in most species; the developed harpe, which is an oblique sclerotized band at the centre of the valva, sometimes bearing large process, or forming small spur near ventral margin; well-developed coremata; the relatively less modified eighth segment; and the setal patches on the third sternite. Some atypical species, T. nivestrota Warren, 1903 ( Papua New Guinea), T. zebrata Warren, 1906 ( Papua New Guinea), T. viridifascia Swinhoe, 1908 (Borneo) , T. effata Prout, 1916b ( Moluccas) and T. interalbata Prout, 1911 (Irian Jaya) have different wing patterns from the transverse lines being replaced by a broad greenish band.

Distribution. China, Japan, Oriental to Australia region, Africa.