G. C.  Steyskal, ?The dipterous fauna of tree trunks?, Papers of the Michigan Academy of Science, Arts and Letters, vol. 35, pp. 121-134, 1949.

G. C.  Steyskal, ?Futher notes on Diptera of tree trunks with descriptions of two new species of _Drapetis_ (Diptera; Empididae) and an abstract of a Finnish paper on Diptera by Tuomikoski?, Papers of the Michigan Academy of Science, Arts and Letters, vol. 38, pp. 255-260, 1953.