Thressa cyanescens (Becker, 1916)
Chalcidomyia cyanescens Becker, 1916: 440. Type locality: Taiwan (Holotypes deposited in Hungarian Natural History Museum, Budapest).
Thressa cyanescens (Becker): Sabrosky 1977: 319; Kanmiya 1983: 236; Nartshuk 1993: 114.
Diagnosis.
Thorax entirely shiny black. Legs yellow except fore coxae black, in male fore femora black except distal part yellow; in female, all femora black except distal part yellow. Wing hyaline without a brown spot near wing apex. Epandrium with 2 narrow bands of sclerite along posterodorsal notch. Cercus small with a concavity on ventral margin.
Distribution.
China: Taiwan; Japan.
Remarks.
Becker (1916) firstly described Chalcidomyia cyanescens from Taiwan. Sabrosky (1977) transferred it to Thressa . Kanmiya (1983) newly recorded Thressa cyanescens from Japan, and gave the figures of male genitalia and abdomen lateral view.