6. gnava -group

(Fig. 11)

Diagnosis. Cercal plate on distal margin with two submedian processes and a short median process which arises from a weakly formed subcercal structure. These processes require further study; the median process is absent in B. jacobaeae, which however clearly belongs to this group. Surstylus with an extended and rounded lobe on the proximal posterior margin in lateral view.

Species included in this group from China are B. aculeifurca (Zhong, 1985), B. chui Suwa, 1996, B. gnava (Meigen, 1826), B. gnavoides (Hennig, 1970), B. nigrodorsata Suwa, 1986, B. sonchi (Hardy, 1872), B. suwai (Wei, 1992), B. tridentifera Suwa, 1986, and B. trifida Suwa, 1986 .