﻿Two new species of the genus Psilalcis Warren, 1893 (Geometridae, Ennominae, Boarmiini) from Hainan, China

﻿Abstract Two new species, Psilalcissubalbibasis Liu, sp. nov. and Psilalcissubconceptaria Liu, sp. nov., are described from Hainan Island, China. Adult males and females of both species, including their genitalia, are figured and compared to closely related species.


Introduction
The genus Psilalcis, belonging to the tribe Boarmiini in the subfamily Ennominae of the Geometridae, was established by Warren (1893) with Tephrosia inceptaria Walker, 1866 from Flores, Indonesia as its type species.Two other new species, Psilalcis atrifasciata Warren and Psilalcis dentilinea Warren, both from Sikkim, were also described as members of this new genus in Warren's article; the former was treated as a synonym of Parapholodes fuliginea (Hampson) by Sato (2000); the latter was transferred to Prochasma by Prout (1926), primarily based on the presence of the metallic mesothoracic crest.Only a few species and subspecies were included in Psilalcis over the following one hundred years (Warren 1899;Inoue 1956Inoue , 1964;;Sato 1993aSato , 1993b)).Subsequently, Holloway [1994] placed Paralcis Warren, 1894 (type species: Menophra conspicuata Moore, 1888) as a synonym of Psilalcis because of the similar genitalic characters and proposed a broad sense of Psilalcis that included the genera Heterarmia Warren, 1895, Polymixinia Wehrli, 1943, and Protoboarmia McDunnough, 1920.He also thought that the genus Phanerothyris Warren, 1895 might be referable to Psilalcis but had a more distinctive valve structure.In addition, he summarized the characters for the whole group, primarily based on the features of the male and female genitalia, and treated four Bornean species as members of Psilalcis with two new species.In the following nearly 30 years, a number of new members, including many newly described species, were added to Psilalcis (Sato 1995(Sato , 1996(Sato , 1998(Sato , 1999(Sato , 2002(Sato , 2008a(Sato , 2008b(Sato , 2013(Sato , 2020(Sato , 2023;;Inoue 1998;Beljaev and Stüning 2000;Orhant 2001;Sato andWang 2006, 2016;Stüning 2018).The present Psilalcis is a complex with large numbers of ZooKeys 1190: 153-162 (2024), DOI: 10.3897/zookeys.1190.115839Bo Liu: Two new species of Psilalcis from Hainan, China species belonging to several different groups on the basis of external characters, and there is evidently much more revisional work to be done.
Recently, two new species, Psilalcis subalbibasis sp.nov.and Psilalcis subconceptaria sp.nov., were collected from Hainan Island, China; the former is similar in external appearance and genitalia to its close relatives P. albibasis (Hampson, 1895), P. benefica (Sato, 1993) and P. sumatrana Sato, 2013; the latter, together with its close relatives P. conceptaria Holloway, 1994, P. paraceptaria Sato, 1996and P. vietnamensis Sato, 1996, share unique features of a trifid valve structure and a setose ampulla at the base of a central laminate lobe on the male genitalia, which perhaps can be treated as a separate group.In the present paper, these two new species are described, and their definitive diagnoses are given with respect to closely related species.

Materials and methods
All specimens of Psilalcis treated herein were collected by light traps on Hainan Island, China and currently are deposited in Coconut Research Institute, Chinese Academy of Tropical Agricultural Sciences, Wengchang, China (CRICA-TAS).For long-term preservation, most of the type specimens of the two new species, including the holotypes, will be transferred to the Institute of Zoology, Chinese Academy of Sciences, Beijing, China (IZCAS) and some of the paratypes will be transferred to the Zoologisches Forschungsmuseum Alexander Koenig, Bonn, Germany (ZFMK).Terminology for wing venation followed the Comstock-Needham System (Comstock 1918) as adopted for Geometridae by Scoble (1992) and Hausmann (2001), and that of the genitalia was based on Klots (1970) and Skou and Sihvonen (2015).Abdomens were removed and placed in 10% NaOH solution for examination of the genitalia.Genitalia were dissected in 10% alcohol solution and stained with Chlorazol Black E. Photographs of adults were taken with a Nikon D750 camera using a Nikon AF-S Micro 60 mm f/2.8GED lens.Photos of genitalia were taken with a KUY NICE E31SPM digital camera attached to a Nikon SMZ745T microscope.
Description.Forewing length: male 12.3 mm; female 13.5 mm.Faces more vivid and contrasty in female.Head.Antennae fasciculate, with moderately long ciliate ventrally in male; filiform in female.Frons not protruding, covered with short scales.Labial palpus curved upwards beyond frons, covered with long, intermingled, dark and fawn scales, third segment not extended in female.Vertex with lamellar, fawn scales, posterior scales erect.Chaetosemata present, small, near eye-margin.Thorax.Patagia and tegulae with lamellar, white, slightly fawn-colored scales, with longer, pale fawn hair-scales on tegulae only.Prothorax ventrally covered with lamellar, white scales.Legs slender, fawn, Figures 1-12.Adults of Psilalcis spp.1-4 Psilalcis subalbibasis sp.nov. 1 male, holotype, upperside 2 male, holotype, underside 3 female, paratype, upperside 4 female, paratype, underside 5-12 Psilalcis subconceptaria sp.nov. 5 male, holotype, upperside 6 male, holotype, underside 7 male, paratype, upperside 8 male, paratype, underside 9 female, paratype, upperside 10 female, paratype, underside 11 female, paratype, upperside 12 female, paratype, underside.Scale bar: 1 cm.chequered black, hind tibia dilated, with a fawn scent brush in male, index of spurs 0-2-4.Forewings with apex angled, termen minutely concave between vein-ends.Fovea present in male, with posterior flexure of the anal vein to accommodate it.Hindwing with apex rounded, termen moderately concave between vein-ends.Wings dark deer-red, mottled dark, with a large white patch at base half, hindwing patch much larger, extending close to submarginal line in male.Antemedial and medial lines dark fawn, faintly visible on forewing, hardly visible on hindwing.Postmedial line fine, dark, slightly sinuous.Discal dot oval, dark, clearly visible, fused with costal patch forming a barred patch on forewing.Submarginal line rather fine, zigzag-shaped, white, faintly visible.Outside of postmedial line bearing a large dark band.Area of apex and between M 3 and CuA 1 on forewing without dark colouration.Distal band present only on upper half of hindwing.Marginal line black, inwardly concave.Fringes identical with the ground colour, interspersed with some dark.Underside brownish-yellow, covered with dark streaks.Distal band similar to upperside, but broader and more prominent.Discal dot clearly visible.Medial line more conspicuous in female.Venation.Forewing: R 1 and R 2 coincident; R 1 +R 2 arising from upper vein of cell, then running almost parallel to the stem of R 3-4 and R 3-5 ; stem of R 3-5 arising shortly before anterior angle of cell; M 2 from nearly the middle of the discocellular vein; CuA 1 from before posterior angle of cell; the base of the anal vein concave downwards.Hindwing: Sc+R 1 running closely parallel but not anastomosing with upper vein of cell at base; Rs from before anterior angle of cell; CuA 1 from before posterior angle of cell; 3A present.Pregenital abdomen.Dorsally scaled white and fawn, scattered with some black scales.Ventrally with pale fawn scales.Setal comb (straight field) of minute setae present on abdominal sternite 3. Tympanal organs moderately sized, without lacinia.A pair of long sterno-tympanal processes present laterally on sternite 1+2, with moderately long free end, reaching the tympanal cavity.Tergite and sternite of segment 7 short, length about 1/2 of width.Tergite and sternite of segment 8 slightly elongate, length approximately equal to width in male.
Female genitalia.Ovipositor slightly elongated, papillae anales narrow, covered with short setae.Anterior apophyses short, about 2/5 length of posterior apophyses.A thin needle-like sclerite present between the bases of posterior apophyses.Lamella antevaginalis narrow, ribbon-shaped.Lamella postvaginalis rather large, strongly sclerotized; centrally squared, distally concave in the middle; lateral processes expanded, bent dorsad, centrally concave inwards.Posterior part of bursa rather short, with an irregular week of narrow sclerotized band.Anterior part of bursa slightly broader than posterior part, but no clear demarcation visible.Signum absent.
Etymology.This new species, Psilalcis subalbibasis, is highly similar to P. albibasis (Hampson) in wing pattern and male genitalia.

Psilalcis subconceptaria
Description.Forewing length: male 12.1-14.5mm; female 13.3-15.0mm.Wing pattern variable among individuals, usually more vibrant in females.Head.Antennae fasciculate, with moderately long ciliate ventrally in males; filiform in females.Frons not protruding, covered with short scales, upper half dark, lower half pale brown.Labial palpus curved upwards beyond frons, covered with long, intermingled, dark and brownish scales, third segment not extended.Vertex with lamellar, brownish scales, posterior scales erect.Chaetosemata present, small, near eye-margin.Thorax.Patagia and tegulae with lamellar, brownish and dark scales, with longer, dark brownish hair-scales on tegulae only.Prothorax ventrally covered with lamellar, brownish scales.Legs slender, yellow, chequered black, hind tibia dilated, with a yellow scent brush in males, index of spurs 0-2-4.Forewings with apex angled, termen minutely concave between vein-ends.Fovea present in males, with posterior flexure of the anal vein to accommodate it.Hindwing with apex rounded, termen moderately concave between vein-ends.Wings brownish, dotted with white and black scales.Postmedial lines of both wings punctuated, sometimes joined in lines, sinuous, black.Medial and postmedial lines of forewing converge below CuA 2 , then separate.Submarginal line very fine, zigzag-shaped, white, faintly visible.Marginal line black, inwardly concave.Distal band serrated, narrow, evident on forewing, only visible near tornus on hindwing.Discal dot small.Fringes colored brownish, interspersed with some black.Underside brownish-yellow, covered with dark streaks.Distal band sometimes absent or not conspicuous on hindwings.Venation.Forewing: R 1 and R 2 coincident; R 1 +R 2 arising from upper vein of cell, then running close to the stem of R 3-4 and R 3-5 ; stem of R 3-5 arising from anterior angle of cell; M 2 from 1/4 of the discocellular vein close to M 1 at base; CuA 1 from before posterior angle of cell; the base of the anal vein concave downwards.Hindwing: Sc+R 1 running closely parallel but not anastomosing with upper vein of cell at base; Rs from before anterior angle of cell; CuA 1 from before posterior angle of cell; 3A present.Pregenital abdomen.Abdomen scaled pale brown, scattered with some black scales.Setal comb (straight field) of minute setae present on the third sternite.Tympanal organs moderately sized, without lacinia.A pair of long sterno-tympanal processes present laterally on sternite 1+2, with moderately long free end, reaching the tympanal cavity.Tergite and sternite of segment 8 strongly elongate in males, length nearly twice the width.Male genitalia.Uncus hood-like, short, weakly curved ventrally, dorsally with short setae.Gnathos and socii absent.Juxta tongue-like, broad at base, slightly pointed at tip.Saccus rounded, slightly extended.Valvae trifid, costal process elongate, cucullus vestigial.Setose ampulla located at the centre of valve laminate lobe.Apex of sacculus bearing a long, strongly curved spine.Valve lamina membranous, distally elongated, central laminate lobe sclerotized.Aedeagus stout, apex with a curved, slender spine, vesica with a cluster of needle-like cornuti on a lateral lobe.
Female genitalia.Ovipositor slightly elongated, papillae anales narrow, covered with short setae.Anterior apophyses short, about 3/5 length of posterior apophyses.The needle-like sclerite between the bases of posterior apophyses absent.Lamella antevaginalis narrow, ribbon-shaped.Lamella postvaginalis very large, centrally triangular, distally triangularly convex at the centre, lateral processes extended, slightly curved dorsad.Posterior part of bursa much narrower than anterior part, rather short, membranous.Anterior part of bursa elongated, posteriorly projected at both sides, with sclerotized corrugations, centrally with a constriction, anteriorly bearing a pair of small, circular, opposed sclerotized patches, with three to five longitudinal ridges.
Etymology.The specific name, subconceptaria, is derived from its closely related species, P. conceptaria.