Orieosia hypopolius (Rothschild, 1916) comb. nov. (Figs 2–3, 10, 13, 16) Lambula hypopolius: Rothschild (1916: 323); Strand (1922: 508) Lectotype (here designated from syntypes): ♀ [Rothschild (1916) mentioned this as ♂], BMNH(E)1325431, [Papua New Guinea], Dampier Isl. [Karkar], Feb. Mch. 1914., Meek’s Exped., #341, Lambula hypopolius Type Rothsch., Rothschild Bequest, B.M. 1939-1. Note: The other ♀ syntype of hypopolius belongs to the next species and is designated to be a paratype of that species (see below). Diagnosis: Like most Orieosia, the species has unicolorous forewings patterned with one tiny dark antemedian spot on the cubital vein and one or two tiny postmedian spots at the end of the cell. In size and pattern O. hypopolius is most reminiscent of O. stenoptera spec. nov., but the forewings are broader in hypopolius with arched costa, those of stenoptera are distinctly narrower with a straight costa. The spots in the cell are somewhat more pronounced in hypopolius than in stenoptera. Patagia of hypopolius broader than in stenoptera. Further distinguishing characters are in the genitalia. Orieosia hypopolius has in the male genitalia the slender sacculus extension at the apex with a knob, in the similar O. orientalis (Hampson, 1909) whereas it is sharp and in tetrastigmata (Rothschild, 1916) this extension is large and broader. The rectangular valve in hypopolius at the apex with one thorn, in orientalis this thorn is longer and positioned centrally, in tetrastigmata this thorn is broad and blunt. The aedeagus of hypopolius bears on the vesica distally three long cornuti and dorsally a scobinated field, in orientalis and tetrastigmata the cornuti are numerous and much smaller. Unfortunately no males of stenoptera are presently known so no comparison is possible with this species. In the female genitalia the antrum of hypopolius is shorter than in stenoptera, in tetrastigmata the antrum is much longer and narrow. The sclerotization of the large bursa copulatrix in hypopolius in the upper part of the bursa is one field of ribs and small spikes, while in stenoptera the antrum is longer and slightly broader with on top of the smaller bursa copulatrix the sclerotized cervix bursae consisting of two sclerotized lobes covered with striae and spikes, in tetrastigmata this sclerotized field is fan-shaped with regular striae and with some tiny spikes. Description: Fwl. ♂ 8.5–9.2 mm, ♀ 8.8–9.6 mm. Male and female almost identical. Antennae in male thicker and serrate, in female ciliate. Head and patagia broad. Antennae, head and thorax pale yellowish-buff. Abdomen grey, legs yellow-buff. Forewings broad with arched costa. Ground colour unicolorous yellowish-buff, scarcely sprinkled with brown scales. Dark brown spots in lectotype all three present, very small, in some specimens the distal lower one may be missing. Fringes short, silvery white with a thin dark fringe line. Hindwings broad triangular, termen slightly concave, in male pale yellowish-grey, apically suffused with grey-buff, in female hindwings unicolorous grey. Male genitalia with tegumen high and slender, uncus thin, curved and with sharp apex. Vinculum wide with a flat saccus. Valvae rather narrow, cucullus distinctly broader than sacculus and almost at full length parallel, at base narrow and at apex narrowing to a sharp thorn. Sacculus narrow, slightly broadening in the middle and apically extended with a slender process, slightly bend and with a knob at the apex. Aedeagus slightly “S”-curved, coecum with straight bottom. Vesica basally with a small field of small spikes, a larger distal field of tiny chitinous drops and distal-ventrally with three to four large needle-shaped cornuti. Female genitalia with a broad and rather long funnel-shaped antrum, continued by a broad coil with sclerotized ribs running into a broad field of sclerotized ribs and spikes in the upper part of the bursa copulatrix. Bursa with a large membranous lobe, the cervix bursae, at the right side with the connection of the ductus seminalis at its base on the underside of this lobe. Bursa copulatrix large and globular with centrally some excentric wrinkles. Distribution: The species is widely distributed on New Guinea, on Karkar Island (Madang Province, Papua New Guinea, former Dampier Island), the mainland of Papua New Guinea (Kokoda, Oro Province), and at a wide distance in the far western part of New Guinea, on the Birdshead Peninsula, the Onin Peninsula and on the Raja Ampat Islands Waigeo and Batanta (Papua Barat, Indonesia).

Published as part of Vos, Rob De, 2022, The genus Orieosia Bucsek, 2012 also found in New Guinea, with description of two new species (Lepidoptera: Erebidae, Arctiinae, Lithosiini), pp. 179-188 in Zootaxa 5188 (2) on pages 180-181, DOI: 10.11646/zootaxa.5188.2.7, http://zenodo.org/record/7087625