Genus Mastrus Förster, 1869

Mastrus Förster, 1869: 176 . Type: Phygadeuon (Mastrus) neodiprioni Viereck, 1911 . Included by Viereck (1911).

Daictes Förster, 1869: 176. Type: Phygadeuon (Daictes) fukaii Viereck, 1911 . Included by Viereck (1911).

A e n o p l e x F ö r s t e r, 1 8 6 9: 1 7 6. Ty p e: A e n o p l e x betulaecola Ashmead, 1896 (= Orthocentrus pilifrons Provancher, 1879). Included by Ashmead (1896).

Seven species, Ma. ecornutus Momoi, 1970, Ma. fukaii (Viereck 1911), Ma. molestae (Uchida, 1933), Ma. oshimensis (Uchida, 1930), Ma. sugiharai (Uchida, 1936), Ma. takadai Momoi, 1970, and Ma. tenuibasalis (Uchida, 1940), have been recorded from Japan. I found more than ten undetermined species from Japan. The taxonomic treatment of these species requires the additional specimens and comparison with European species. In this study, I re-describe Ma. molestae and record some distributional data of this species and Ma. takadai below.