Oxyambulyx japonica Rothschild, 1894, Novit. zool. 1: 87. Type locality: Japan: Kiushiu [Kyushu].
Sexually dimorphic. In the male genitalia, abdominal sternum A8 with two tubercles internally near middle of apical margin and which are a little higher and father apart than in Ambulyx subocellata. Gnathos less deeply sinuate than in Ambulyx placida. Harpe resembling that in Ambulyx placida: ventral process triangular, pointed; other process composed of two lamelliform ridges the upper edges so bent towards each other that a hollow cylinder if formed and produced distad. Aedeagus somewhat bent, its apical edge developed into a short, strongly chitinised hook.
Japan: 5-27.v (Honshu); 2.vi (Honshu); 14-28.vi (Honshu); 1-16.vii (Honshu); 29.vii (Tsushima).
Larval hostplants. Recorded from Acer (Inoue et al., 1982) and Carpinus japonica (Nakamura, 1977). Yano (1994) reared it on Carpinus laxiflora and C. tschonoskii. Juglans mandschurica and Rhus javanica were refused.
Japan: Honshu (Takao-San; nr. Hinoharu; Tokyo; Mikaboyama, 750m; Namezawa Spa, 700m; Bushi; Mononoki Spa, 950m); Shikoku; Kyushu; Tsushima (Sasuna).
Endemic to Japan.