Arctornis harpeforma Yuan & Wang, 2025

Arctornis harpeforma Yuan & Wang View in CoL sp. nov.

Diagnosis. The new species is similar to the above new species in external morphology, but can be separated from the latter by the forewing having a black dot in the discal cell, male genitalia with a bilobate uncus, and a sickle-shaped process originating from the dorsal base of the valva.

Description. Male adults ( Figs. 3–4, 6, 8 View FIGURES 1–8 ). Forewing length 13–14 mm. Frons and vertcx covered with orange hairs. Labial palpus red. Antenna bipectinate, pale orange. Thorax and abdomen white. Forewing and hindwing both white, with brown hairs on termen. Forewing costa orange about distal 1/4, with a black dot in discal cell. Wing venation light green, forewings with vein R 3, R 4 and R 5 stalked, M 1 arising from near the upper angle of discal cell, M 2 originating from near the lower angle of discal cell; hindwing with Rs and M 1 arising from the upper angle of discal cell, M 2 present. Legs white, with orange hairs terminally, forelegs less; hindlegs with a pair of white tibial spurs.

Male genitalia ( Fig. 10 View FIGURES 9–11 ). Uncus bilobate, well sclerotised apically. Valva lightly sclerotised, approximately rectangle, upper left corner slightly pointed, with a sickle-shaped process originating from dorsal base. Juxta weakly sclerotised. Aedeagus short, with a forked sclerotization terminally.

Larvae ( Figs. 20–27 View FIGURES 20–27 ). First instar body length 2. 8 mm, dorsal side dark green, with white blotches; second instar dark green dorsally, throacic verrucae with orange bristles; third, fourth and fifth instars with two black dots and a cluster of brown bristles on a white blotch at the dorsal side between A3 and A4; fourth and fifth instars with two black longitudianl stripes on the dorsalateral side of body; head orange in the first three instars, black in the final two instars; forns with a yellow inverted V-shaped stripes along ecdysial suture; middorsal gland small and transparent in all instars.

Host-plant. ( Fig. 28 View FIGURE 28 ): Castanopsis fissa . (Champ. ex Benth.) Rehd. et Wils. ( Fagaceae )

Type material. Holotype: ♂, Fenghuangshan Provincial Nature Reserve , Chaozhou, Guangdong, China, 23º53’3.5376” N, 116º35’46.896” E, altitude 600 m, 9-V-2024, leg. Ziqi Yuan. GoogleMaps Paratypes: 3♂, 1♀, same collecting data as holotype GoogleMaps .

Distribution. China (Guangdong).

Etymology. The new species is named after the sickle-shaped protrusions on both sides of the valva in the male genitalia.

Remarks. Female adults of this new species are not described in the present paper for the following reasons: the only female adult specimen collected from field has been severely damaged after laying eggs during transportation, and no female adults have been successfully reared with its eggs.