Philampelus naga Moore, , in Horsfield & Moore, Cat. lepid. Insects Mus. Hon. East-India Company 1: 271. Type locality: [India, West Bengal,] Darjeeling [Darling].
Synonym. Philampelus naga Moore, 1858.
Synonym. Acosmeryx metanaga Butler, 1879.
Wingspan: 86--112mm. The most conspicuously marked species of the genus, easily distinguished by the pattern of its forewing. Forewing upperside with a brown discal band extending from the costa towards the middle of the distal margin, sharply defined anteriorly, the triangular area anterior to it grey; a well-defined, grey submarginal band running more or less straight from vein Rs4 to the tip of 1A+2A.
In the male genitalia, gnathos parallel-sided. Harpe with process quite acute distally, resembling a hand with the thumb lying alongside the forefinger, with the other fingers curved back and upwards. Aedeagus with left lobe shorter than in all other species of Acosmeryx. In the female genitalia, ostial plate similar to that in Acosmeryx anceus anceus.
China: 29.iv (Beijing); v (Zhejiang; Guangdong); vi (Yunnan; Hainan; Beijing); vii (Xizang/Tibet). Taiwan: 19.ii (Taoyuan Hsien); iii-v (Kaohsiung Hsien); vi (Hualien Hsien). North Korea: 15-29.v (North Pyongan Province). Japan: 30.iii (Kyushu); 25.iv (Honshu); 3-31.v (Honshu); 17.vi (Honshu); 20.vi (Ryukyu Archipelago); 26.v-26.vi (Hokkaido). Russia: 1-20.vii (Primorskiy Kray; Kurile Islands).
In northern China there is one generation per year, with adults flying between April and June (Yang, 1978).
Park et al. (1999) give early May until mid August as the flight period in Korea.
OVUM: A deep rich green, becoming whitish before hatching, almost spherical, smooth (Bell & Scott, 1937).
LARVA: Full-fed 80--100mm. Dichromatic: green or brown. According to Bell & Scott (1937), in the first instar, the head and body are green, the horn black, long and straight. In the second instar, thoracic segment 1 is as narrow as the head, with the body tapering sharply anteriorly from the first abdominal segment. The black horn is still long and straight, but reddish at the base and with a white tip. The head and anal segments are yellow, the body green dotted with white, with the spiracle of abdominal segment 1 surrounded by a black spot. A yellow dorso-lateral stripe runs from the head to the horn. This colour pattern remains the same for the next two instars, but a lateral flange develops on the third thoracic and first abdominal segments and a yellow ventro-lateral stripe appears on the thoracic segments and abdominal segment 1. In the final instar of the green form, the head is grass-green, with a narrow, pale yellowish dorso-lateral stripe and a broader stripe of the same colour separating face from cheek; thoracic segments 1 and 2 grass-green with short darker stripes; the rest of the body bluish green, mottled with yellow above the dorso-lateral stripe and pale greyish blue below. The dorso-lateral stripe is narrow and white on thoracic segments 1 and 2, broader and pale yellow on thoracic segment 3 and abdominal segment 1, then white to the base of the horn, and edged narrowly above with orange on segments 3--7. The narrow, white ventro-lateral stripe on thoracic segments 1 and 2 becomes broad and yellow as it outlines the flange before turning upwards on abdominal segment 1 to form an oblique stripe. There are also pale yellow, oblique lateral stripes on segments 1--7. The horn is lilac-grey dotted with purple. There are dark purple patches on the body above the bases of the legs, increasing in size caudally, and extending along the lower edge of the flange on thoracic segment 3 and abdominal segment 1. Upper part of prolegs bluish, the lower part pale yellow; feet brown, anal clasper bluish, anal flap edged broadly with pale yellow. Spiracles deep orange. In the brown form the green pigmentation is replaced by pinkish brown. The whole body is smooth and moderately shiny.
At rest on the underside of a leaf or stem, the larva throws back its head and anterior segments in a sharp curve, the head held so that the face is in the same plane as the dorsum of thoracic segment 1. The thoracic legs are pressed close to the body and the flange is dilated laterally. Alarmed larvae withdraw their heads and first two thoracic segments into segment 3; thoracic segment 3 and abdominal segment 1 are puffed out and the flanges further dilated.
PUPA: 44--55mm long, 15mm wide. Very similar in shape to Clarina but colour of dorsum dark brown, sides and venter paler brown, abdomen marked with short darker stripes and pits dark brown. There is a pale brown patch in front of the eye; hind bevels of segments 8 to 11 dark brown; spiracles black ringed by dark brown; cremaster nearly black. Shape as in other Acosmeryx pupae, with the hind margin of segment 11 deeply undercut. Surface shiny, shallowly but coarsely pitted on segments 4 to 7 and 12 to 14. Segment 2 is finely, irregularly, longitudinally striate. Segment 8 with a patch behind the spiracle, finely, regularly, transversely striate. Front bevels of 9 to 11 finely pitted; rest of pupa smooth. Spiracle of segment 2 covered by a narrow transverse lobe projecting from the front margin of 3, the front edge of the lobe sharply raised. The remaining spiracles are shortly oval, flush, the edges of the: central slit raised. Cremaster small (2mm), basal half bulbous, distal half a cylindrical shaft ending in two small hooks. Dorsal surface of basal half honeycombed, shaft smooth (Bell & Scott, 1937).
Formed in a slight cocoon on the ground. Very sensitive to desiccation (Shchetkin, 1956), but highly tolerant of moisture. The overwintering stage.
Larval hostplants. Various species of Vitis, Cayratia and Ampelopsis (Vitaceae), such as Vitis amurensis, Ampelopsis brevipedunculata and Ampelopsis heterophylla in the Russian Fart East. In Shanxi also recorded from Actinidia chinensis (Li & Guo, 1990).
Recorded in Korea on Stathmopoda auriferella, Ampelopsis brevipedunculata and Vitis vinifera (Vitaceae) (Park et al., 1999).
China: Liaoning (Changhai, Dachangshan Island); Hebei; Beijing (Baihua Shan; Badaling National Forest Park); Shanxi (Taiyuan; Xiaxian); Shaanxi; Henan (Mt. Niuxinduo, Luoyang, 1763m); Anhui (Mt. Huang Shan); Zhejiang (Tianmu Shan); Hubei (Badong; Wuhan); Sichuan (Pengshui; Wulong); Chongqing (Fengjie); Yunnan (nr. Yingjiang, 1180-2080m; Gaoligong Shan); Guizhou (Jiucai Ling; Xinzhaidashan, Zhijin County, 1000-2000m); Tibet/Xizang (Mutu, Namjagbarwa region, 850m; Zhangmu, 2200m; Langmai, Gonjo County (30°45'N, 98°52'E)); Hunan (Dayong); Guangdong (Nanling National Forest Park, 1100m); Hainan (Sanya, Mt. Jianfengling; Duowen Ling, nr Lingao; Longhushan, Wenchang City).
Taiwan: Hualien Hsien (Taroko National Park); Kaohsiung Hsien (Shanping; nr. Tuona, 15km SE of Shanping, 1050m); Taipei Hsien (Fushan); Taipei (Shinshan Dream Lake, Sih-ji); Nantou Hsien (Lianhuachih); Taoyuan Hsien (Taoyuan City).
North Korea: North Pyongan Prov. (Chonma County, Chonma-san).
South Korea: Baengnyeong-do & Daecheong-do; Seoul; Kyonggi Prov.; Kangwon Prov.; North Chungchong Prov.; South Chungchong Prov.; North Cholla Prov.; South Cholla Prov.; North Kyongsang Prov.; South Kyongsang Prov.; Cheju Prov.
Japan: Hokkaido (Hakodate; Sapporo); Honshu (Tokyo; Kiyosato, 1300m; Mikaboyama, 750m; ); Shikoku; Kyushu (Nishinakama); Ryukyu Archipelago (Okinawa; Miyakoshima).
Russia: Primorskiy Kray (Khasan; Lazovskiy nature reserve; near Zanadvorovka; 20 km SE of Ussuriisk; Kravtsovka; Anisimovka; Krounovka); Kurile Islands (Kunashir Island).
As subsp. naga, from the Himalayan foothills of Pakistan (Rafi et al., 2014), India, Nepal (Haruta, 1992) and Bhutan across southern and eastern China (Bell & Scott, 1937) to Taiwan, Korea, Japan (D'Abrera, 1986) and the Kurile Islands (Rybalkin & Yakovlev, 2017). Also Burma/Myanmar, Thailand, Laos, Vietnam (Sa Pa) and Peninsular Malaysia. Several migrants have been reported from the Russian Far East since 2002-2003 (Beljaev, 2003); it may even have established a resident population southeast of Ussuriisk (Dubatolov, pers. comm. 2013).
[As subsp. hissarica, only southern Tajikistan (Shchetkin, 1949; Shchetkin, 1956; Derzhavets, 1984) and Afghanistan (Ebert, 1969; Daniel, 1971; C. M. Naumann, pers. comm.).]
[It should be noted that some of the individuals of this subspecies recorded from southern China and northern Vietnam may, in fact, be the newly-described Acosmeryx purus Kudo, Nakao & Kitching, 2014.]
Holarctic; eastern Palaearctic region. Pleistocene refuge: Polycentric.