Psilalcis subalbibasis, Liu, 2024

Liu, Bo, 2024, Two new species of the genus Psilalcis Warren, 1893 (Geometridae, Ennominae, Boarmiini) from Hainan, China, ZooKeys 1190, pp. 153-162 : 153

Psilalcis subalbibasis sp. nov.

Figs 1-4 , 13 , 15 , 18

Type-material.

Holotype: ♂, China, Hainan Province, Lingshui, Diaoluoshan, 922 m, 19.VI.2023, Bo Liu leg., gen. prep. no. CRICATAS00112 (CRICATAS, will be transferred to IZCAS in the future). Paratype: 1 ♀, China, Hainan Province, Lingshui, Diaoluoshan, 922 m, 19.VI.2023, Bo Liu leg., gen. prep. no. CRICATAS00113 (CRICATAS, will be transferred to IZCAS in the future).

Diagnosis.

Psilalcis subalbibasis is very similar in appearance to its close relatives P. albibasis ( Sato 1999: 37, figs 19, 40; Sato 2020, pl. 25: 18), P. benefica ( Sato 1993a: 18, pl. 36: 21, fig. 153; Sato 1999: 37; Sato 2013, figs 28, 36; Sato 2020, pl. 25: 17) and P. sumatrana ( Sato 2013: 250, 251, figs 16-18, 27, 35), all of which have a similar wing pattern of white basal half and reddish-brown terminal half together with a broad dark band. It can be distinguished from its relatives by the following genitalia characters: 1) cucullus crescent-shaped, strongly concave apically in P. subalbibasis , triangular and not concave apically in the other three closely related species; 2) setose ampulla narrow at base and broad at apex; and 3) female genitalia with a rather large, sclerotized, uniquely constructed lamella postvaginalis.

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, 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 M3 and CuA1 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: R1 and R2 coincident; R1+R2 arising from upper vein of cell, then running almost parallel to the stem of R3-4 and R3-5; stem of R3-5 arising shortly before anterior angle of cell; M2 from nearly the middle of the discocellular vein; CuA1 from before posterior angle of cell; the base of the anal vein concave downwards. Hindwing: Sc+R1 running closely parallel but not anastomosing with upper vein of cell at base; Rs from before anterior angle of cell; CuA1 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.

Male genitalia. Uncus hood-like, base broad, triangular, apex short, strongly sclerotized, curved ventrad at 90 degrees, with strong setae dorsally. Gnathos vestigial, socii not visible. Juxta short, basally broad, apically slightly bifurcated. Saccus rounded, slightly extended. Valvae parallelogram, costa rod-shaped. Cucullus dilated, crescent-shaped, strongly concave apically. Setose digitate ampulla located at the ventral edge of the valve costa, narrow at base, dilated at apex. Valve lamina membranous, central laminate lobe weakly sclerotized. Sacculus sclerotized, distally with a short, slightly inwardly curved spine-like process. Aedeagus short, apex tapering, with a minute spine near the tip. Vesica without cornuti.

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.

Distribution.

China (Hainan).

Figures

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.

Figures 13, 14. Male genitalia of Psilalcis spp. 13 Psilalcis subalbibasis sp. nov. paratype, gen. prep. no. CRICATAS 00112 14 Psilalcis subconceptaria sp. nov. paratype, gen. prep. no. CRICATAS 00143. Scale bar: 1 mm.

Figures 15 - 17. Female genitalia of Psilalcis spp. 15 Psilalcis subalbibasis sp. nov. paratype, gen. prep. no. CRICATAS 00113 16 Psilalcis subconceptaria sp. nov. paratype, gen. prep. no. CRICATAS 00146 17 Psilalcis subconceptaria sp. nov. paratype, gen. prep. no. CRICATAS 00147. Scale bars: 1 mm.

Figures 18 - 21. Living specimens of Psilalcis spp. 18 Psilalcis subalbibasis sp. nov. female 19 Psilalcis subconceptaria sp. nov. male 20 Psilalcis subconceptaria sp. nov. female 21 Psilalcis subconceptaria sp. nov. female.