Macroglossa imperator Butler, 1875, Proc. zool. Soc. Lond. 1875: 243. Type locality: Ceylon [Sri Lanka].
Synonym. Macroglossum mitchellii chinensis Clark, 1928.
Wingspan: 55--74mm. Easily recognized by the head and thorax being marked with a very dark broad median stripe which divides the pinkish-grey surface into two stripes. Black discal band of fore wing triangularly dilated behind M1, joining the subapical and apical, black spots. Median band of hind wing deep yellow, at M3 about as wide as the marginal border.
In the male genitalia, uncus truncate-sinuate, angle rounded. Gnathos swollen at the rounded apex. Valve with stridulatory scales. Harpe similar to that of Macroglossum heliophila, obtuse, somewhat upcurved apically, not dentate. Aedeagus with process similar to that of Macroglossum heliophila, more curved proximad, the thin apical part not quite so long.
Attracted to light after dusk, but also flying by day in dull, damp weather.
China: 28.iii-12.iv (Hong Kong); 14.v (Hong Kong); vi (Yunnan); 28.viii (Yunnan). Taiwan: iii (Chiai Hsien); iv (Kaohsiung Hsien); vi (Kaohsiung Hsien; Taichung Hsien); vi-viii (Hualien Hsien); viii (Chiai Hsien); x (Taichung).
Larval hostplants. Unknown.
China: Yunnan (Kunming; Laojun Shan, 2579m; nr. Lüchun, 1900m; Pingdi; Jinghong; Simao/Pu'er; Gaoligong Shan); Guizhou (Jiangkou; Leishan); Guangdong (Nanling National Forest Park); Hong Kong (Kwun Yum Shan).
Taiwan: Hualien Hsien (Taroko National Park); Taichung; Taichung Hsien (Anmashan, 2230m); Kaohsiung Hsien (6km NNW of Shanping, 850m; Liukuei); Taipei Hsien (Fushan); Chiai Hsien (Alishan, 7500').
Sri Lanka, southern and eastern India, Thailand, southern China, Taiwan, Vietnam, Malaysia (Peninsular, Sarawak), Indonesia (Sumatra, Kalimantan).
Subsp. mitchellii Boisduval, , is from Java.