Tylostega vittiformis, Liu & Wang, 2019

Liu, Ping & Wang, Shuxia, 2019, Two new species of the genus Tylostega Meyrick, 1894 (Lepidoptera: Crambidae) from China, with a list of all the known species in the world, Zoological Systematics 44 (3), pp. 206-211 : 208-209

Tylostega vittiformis sp. nov. ( Figs 2 , 5 )

Diagnosis. This species is characterized by the wings with obviously diffused blackish brown scales. It is similar to T. tylostegalis (Hampson, 1900) in the male genitalia, but it can be separated by the valva with a curved, bandlike median projection, the phallus with one spine-like and two Y-shaped cornuti, and the dorsal margin of the sacculus without denticles. In T. tylostegalis , the valva has a small triangular median projection, the phallus has two shorter and one longer spine-like cornuti, and the dorsal margin of the sacculus bears denticles (Du & Li, 2008: fig. 8).

Description. Adult ( Fig. 2 ) wingspan 20.0 mm. Head yellowish white. Antenna yellowish brown, male antenna with ventral cilia shorter than diameter of flagellomere. Labial palp with 1 st and 2 nd segments yellowish white except 2 nd segment with distal 2/5 and dorsal surface fuscous; 3 rd segment yellowish brown. Maxillary palp yellowish brown, tipped with fuscous. Proboscis with yellowish brown scales at base. Patagium, tegula and thorax yellow, mixed with blackish brown scales. Forewing ground color yellow, with diffused blackish brown scales, with blackish brown spots at base; antemedial line blackish brown, extending from basal 1/4 of costa to middle of upper margin of cell, then excurved to basal 1/3 of dorsum; depression before discoidal stigma, covered with a small yellow flat scale-tuft mixed with black on dorsal surface, with dense yellowish white mixed with brown scale-like pecten on ventral surface in male; discoidal stigma blackish brown, barlike; postmedial line blackish brown, extending from distal 1/3 of costa to M 2, thereafter arched outward to near base of CuA 2, finally excurved to distal 1/3 of dorsum; terminal domain blackish brown; black spots along terminal margin; cilia yellowish brown. Hindwing yellow with diffused blackish brown scales; discoidal stigma blackish brown; black spots along terminal margin; cilia yellowish brown. Legs yellowish white, black at apices of each tarsomere and of all tibiae, and on outer surface of basal 1/3 of middle tibia.

Male genitalia ( Fig. 5 ). Uncus slightly narrowed from broad base to rounded apex, with height greater than basal width slightly, setose along lateral margin of distal 2/3 and distally. Valva subparallel from base to basal 2/3, gradually narrowed from distal 1/3 to rounded apex; median projection bandlike, curved outward, bifurcate distally; costa gradually narrowed from base to before apex; sacculus concave at basal 1/3 on dorsal margin, arched in middle, subparalle from distal 1/3 to apex, terminating beyond ventral half of valva. Saccus sub-semicircular, obtusely rounded on anterior margin. Juxta heartshaped, rounded on anterior margin, concave on posterior margin, produced posterolaterally. Phallus about half length of valva, with one spine-like and two Y-shaped cornuti.

Female. Unknown.

Type material. CHINA, Yunnan: Holotype ♂, Yexianggu (22.17°N, 100.87°E; elev. 762 m), Xishuangbanna, 17 July 2014, leg. Kaijian Teng, Wei Guan, Xiuchun Wang & Shurong Liu, slide No. LP18007 . Paratype. 1♂, Lvshilin, Xishuangbanna Nature Reserves, 21 May 2015, leg. Zhenguo Zhang, slide No. LP18033 .

Distribution. China (Yunnan).

Etymology. The specific name is derived from the Latin vittiformis , referring to the bandlike median projection of the valva.

Figures

Figures 1–2. Tylostega spp., adult. 1. T. longicornuta sp. nov., male, holotype. 2. T. vittiformis sp. nov., male, holotype. Scale bars= 2.5mm.

Figures 3–6. Tylostega spp., genitalia. 3. T. longicornuta sp. nov., male genitalia, holotype, slide No. LP18045. 4. Ditto, female genitalia, paratype, slide No. LP18044. 5. T. vittiformis sp. nov., male genitalia, slide No. LP18007. 6. T. serrata Du & Li, 2008, female genitalia, slide No. LP17985. Scale bars: 3, 5=0.5mm; 4, 6=1.0mm.