Fossia Volynkin, Ivanova

Huang, Chu-Yang, Volynkin, Anton V., Zhu, Li-Juan, Wang, Min & Huang, Si-Yao, 2021, Contribution to the knowledge of the genus Fossia Volynkin, Ivanova & S. - Y Huang, 2019 (Lepidoptera: Erebidae: Arctiinae: Lithosiini) from China with description of a new subspecies, Zootaxa 5023 (2), pp. 284-292 : 286

The genus Fossia Volynkin, Ivanova & S.-Y. Huang, 2019

Diagnosis. Species of the genus are small-sized moths with a bright reddish ground color and blackish transverse lines. The sexual dimorphism is well expressed: males are small and dark with narrower wings, while females are significantly larger and more reddish with broader wings. In the male genitalia, Fossia is characterized by the heavily sclerotized and dorsally bilobate juxta, the absence of a distal membranous lobe in valva, the narrow sacculus with a strongly sclerotized medial process and a blunt distal process, the small and straight aedeagus with the vesica consisting of a large membranous ventral diverticulum and a conical medial dorsal diverticulum covered with a prominent cornuti field. In the female genitalia, Fossia can be easily distinguished from other related genera by the following autapomorphies: 1) the presence of a heavily sclerotized bilobate antevaginal plate fused with the 8 th sternite and having a very narrow ostium bursae in its middle part; 2) the presence of a short and narrow but heavily sclerotised antrum which is fused with the antevaginal plate; and 3) the elliptical corpus bursae which is weakly scobinated and beaing one elliptical signum ( Volynkin et al. 2019).

Morphology. Adult. Antenna black, densely ciliate in male and nearly filiform in female. Head red or orange, with one black spot medially. Patagia and tegula red or orange, tegula with one black spot medially. Thorax red or orange, with blackish spots and longitudinal band. Abdomen black in males and black with reddish tip in most of females (except for female of F. punicea rothschildi ( Draudt, 1914) having orange abdomen). Forewing pattern blackish. Subbasal area with short longitudinal streak. Antemedial and medial lines convex medially. Postmedial line sinuous. Submarginal area with short streaks. Cell with dot-shaped discal spot. Hindwing black with red or orange area along the costa in male and orange to red with blackish suffusion at outer and inner margins in female. Cilia blackish in both sexes. Male genitalia. Uncus slender, medially curved, apically pointed. Tegumen narrow. Vinculum moderately long. Saccus broad. Juxta shield-like, bifid apically. Valva strongly sclerotized, broad, lacking membranous part. Costa with medial and distal processes. Sacculus with medial process of different length and stout distal process. Aedeagus short and narrow, vesica consisting of conical dorsal diverticulum and sack-like ventral diverticulum. Female genitalia. Papilla analis rectangular, broad and short. Apophyses posteriores equal in length to apophyses anteriores. Antevaginal plate strongly sclerotized, with bifid posterior end. Ostium bursae narrow. Ductus bursae membranous and very short. Corpus bursae elliptical, covered by spinulose scobination and bearing weakly sclerotized signum. Appendix bursae membranous, situated postero-medially.