Vol. 37, pp. 25-42 February 21, 1924 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON ^^^. FLIES OF THE FAMILY DROSOPHILIDAE OF THE..^ii;ss>^ DISTRICT OF COLUMBIA REGION, WITH KEYS TO GENERA, AND OTHER NOTES, OF BROADER APPLICATION. BY J. R. MALLOCH AND W. L. McATEE. The group of flies associated together in this paper under the family name Drosophihdae consists in large part of those genera so placed by other authors, and in smaller part of genera in-cluded in Geomyzidae by authors. Nowhere in the order is there so much diversity of opinion as to family limits, as is evident in the case of this and alHed famihes of the Acalyptrata. In order to crystalHze opinion in so far as this family is con-cerned we put forward the following list of characters as criteria for the recognition of Drosophihdae. Though it may be that some exotic forms will not come into entire alignment with this summary we believe that taken as a whole these characters will hold throughout the world. Family characters: Vibrissae present, in the normal position; each orbit with at least two bristles, one of which is directed straight forward; wing with auxiliary vein present, usually in-complete, always very close to first vein; anal cell always pres-ent; anal vein present or absent, when present never complete; costa either distinctly or indistinctly broken just beyond humeral vein and again at apex of auxiliary (i. e., just in front of apex of first vein); some or all of the tibiae with a weak preapical dorsal bristle or setula; spiracles of abdomen in mem-brane; postvertical bristles convergent; all North American genera with at most two pairs of distinct dorsocentrals, except in one species, Scaptomyza vittata Coquillett. The larvae are very similar to those of Ephydridae, possessing 3— Pboc. Biol. Soc. Wash., Vol. 37, 1924. (25)
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