Genus Ceriomydas WillistonOeriomydasWilliston, 1898: 58. Type-species,fraudulentus Williston(orig. des.). The original description is as follows: "Like Mydas J but the abdomen as in Ceria or Oonops. The abdomen is pedunculate, much narrower at the base, broadly expanded and acuminate distally; the first two segments are tapering, the third cylindrical, with parallel sides, and nearly twice as long as wide; the fifth segment is as broad as the thorax, whence the abdomen tapers to a point. The face is more produced downwards than in Mydas) and the labella are larger. There is a marginal cross-vein in the wings, and the hind tibiae are spurred". In the description of [raudulentue Williston stated "lamella (antennal club) altogether about three-fourths the length of the third joint. - Length 27 mm.". "One specimen (~), Chapada, Brazil (H. H. Smith). This specimen shows a remarkable mimicry of certain ones of Oonops occurring in the same region". The female abdomen is narrowed basally in a few species of Mydas. This is probably most evident in Mydas tricinctus Bellardi; in dorsal view tergite 3 is one and one-half times as broad as long. A photograph of Oeriomydas irouduientus Williston was published by Williston (1908: 18, fig. 3), and Curran (1934: 480). The genus is known only from the type, which could not be located.

Published as part of J. Wilcox & N. Papavero, 1971, The American Genera of Mydidae (Diptera), with the Description of three new Genera and two new Species, pp. 41-119 in Arquivos de Zoologia 21 (2) on pages 80-81, DOI: 10.5281/zenodo.154004