More evidence is awaited. B. sushkini and B. saltuarius for two separate species. Oriental, Palaearctic Regions. The two taxa are closely similar. Depending upon the species concept embraced, such subtle differences as those between B. reinigiellus and B. hortorum might be expected even within a single population and I shall treat all three taxa as conspecific for the present.
More evidence is awaited.
See comments on B. ruderatus . Whether or not the taxa on either side of this hybrid zone are considered to be separate species therefore depends on which species concept is preferred. B. notocastaneus was described from a single male from Hubei. From the description, it appears most likely to be conspecific with B. koreanus . Oriental, Palaearctic Regions.