Wing of male of Dolichocephala argus from Steyskal and Knutson (1981, fig. 25) [1].

References

1. Steyskal G.C., Knutson L.V.
   (1981) Empididae. in: McAlpine J.F. (Ed.), Manual of Nearctic Diptera. Agriculture Canada, Ottawa, pp. 607-624.