Oreta Walker, 1855

Oreta Walker, 1855, List Specimens lepid. Insects Colln Br. Mus., 5: 1166. Type species: Oreta extensa Walker, 1855, by subsequent designation by Kirby, 1892. East Indies.

Dryopteris Grote, 1862, Proc. Acad. Sc. nat. philad., 1862: 360. Type species: Drepana rosea Walker, 1855, by subsequent designation by Grote, 1863. Canada: Nova Scotia.

Hypsomadius Butler, 1877, Ann. Mag. nat. Hist., 4 (20): 478. Type species: Hypsomadius insignis Butler, 1877, by monotypy. Japan: Yokohama.

Holoreta Warren, 1902, Novit. zool., 13: 340. Type species: Cobanilla jaspidea Warren, 1896, by original designation. Australia: Queensland, Cedar Bay, south of Cooktown.

Oretella Strand, 1916, Arch. Naturgesch., 81(A) 12: 164. Type species: Oreta (Oretella) squamulata Strand, 1916 (= Oreta loochooana Swinhoe, 1902), by monotypy. China: Formosa [Taiwan].

Psiloreta Warren, 1923, in Seitz, Macrolepid. World, 10: 485. Type species: Oreta sanguinea Moore, 1879, by original designation. India: Darjeeling.

Mimoreta Matsumura, 1927, J. Coll. Agr. Hokkaido Univ., 19: 46. Type species: Mimoreta horishana Matsumura, 1927 (= Oreta griseotincta Hampson, 1893), by original designation. China: Formosa [Taiwan].

Rhamphoreta Bryk, 1943, Ark. Zool., 34A (13): 25. Type species: Oreta (Rhamphoreta) eminens Bryk, 1943, by original designation. Burma [Myanmar]: north-east, Kimbaiti.

Diagnosis. Watson (1967) presented a detailed description of Oreta. Holloway (1998) and Park et al. (2011) presented definitive apomorphic features of this genus. The main diagnostic features are summarized as follows: the moths are reddish, sometimes partly yellowish, or dark brown; often with a distinct oblique postmedial line from forewing apex to hind margin; usually with a well developed falcate forewing, which is occasionally not falcate or bifalcate; sometimes external sexual dimorphism is present. In the male genitalia, the uncus is broad, usually slightly bilobed, and occasionally totally bilobed; the gnathos is well developed, usually rod-shaped; the valva is small, very short to long, rounded, with a large spur or other process from the sacculus; the saccus is often distinctly expanded; the eighth abdominal sternite usually bears lateral processes. In the female genitalia, the rounded ovipositor lobes are simple or slightly bilobed, surrounded by sclerites. Forewing venation: areole present; R1 diverging before upper angle of cell or from base of areole; R2 and R5 diverging near the distal part of the areole respectively, M2 close to M3. Hind wing venation: Sc+R1 and Rs close to each other for a distance distal to upper angle of cell, then separate rapidly; M2 close to M3 or stalked with M3.

Biology. Larvae feed on Viburnum (Caprifoliaceae), Cinnamomum (Lauraceae) (Inoue 1982), Coffea, Mussaenda, Pavetta, Randia, Uncaria and Wendlandia (Rubiaceae) (Holloway 1998).

Distribution. Abundant in the Oriental Region, rare in the Palaearctic, Nearctic and Australian Regions.

Remarks. Watson (1967) recognized six species-groups based on external and genital characters: the rosea, insignis, extensa, fuscopurpurea, carnea and rubromarginata species groups. Most Chinese species fall into the rosea species group: O. vatama Moore, 1866, O. andrema Wilkinson, 1972, O. obtusa Walker, 1855, O. speciosa (Bryk, 1943), O. brunnea Wileman, 1911, O. shania Watson, 1967, O. loochooana Swinhoe, 1902, O. pulchripes Butler, 1877, O. turpis Butler, 1877, O. hoenei Watson, 1967, O. paki (Inoue, 1964), O. ancora Wilkinson, 1972, O. flavobrunnea Watson, 1967, O. pavaca Moore, 1866, O. trispinuligera Chen, 1985, O. trispina Watson, 1967, O. sanguinea Moore, 1879, O. liensis Watson, 1967, O. eminens (Bryk, 1943), O. inflativalva sp. nov. and O. angularis Watson, 1967. The extensa, fuscopurpurea, carnea, and insignis species groups contain only one Chinese species each. No species in the rubromarginata species group has been recorded in China. O. bilineata has not been placed into any known species group since the male is unknown.

Many species in the rosea species group have two colour forms, named the yellow and brown and brown forms by Watson (1967). In the first form, the forewing is divided into two parts by the oblique postmedial fascia from apex to hind margin — the reddish brown to brown basal part (often pale brown or yellowish basally) and the distal yellow part (not including the brown marginal band); the hind wing has a small reddish brown basal part (sometimes with yellow base) and a large yellow distal part, sometimes with an apical band or patch. In the second form, there is no yellow coloration posterior to the postmedial fascia. Our work so far shows that O. obtusa, O. flavobrunnea, O. loochooana, O. pulchripes, O. trispina, O. liensis, O. brunnea, O. hoenei inangulata have two colour forms, while other species only have one form, either yellow and brown or brown.

In the rosea species-group, the species from O. ancora to O. eminens, have a broad uncus, large and blunt valva, slender median process of gnathos, variously decorated sacculus (except in O. eminens), and a developed saccus. The aedeagus has a tapering to blunt posterior process, lacking cornuti on the vesica (except in O. pavaca).