and the original description from MATSUSHITA Masaki, 1941.Zur Kenntnis der japanischen Cerambyciden (VI).Insecta Matsumurana, Sapporo 15 (4): 151-158, 3 figs.
Xavier, thank you for this description which fits well with the specimen. And I agree with Cuong: it makes no doubt that this is a female of D. igai. The confusion comes from the fact that I had a series of "igai" in my collection which are Dorysthenes (Prionimimus) pici...