52 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 74 



100. Mid tibia with one loug apical ventral bristle, the other two bristles re- 

 duced to very short setiilae; hypopygium as Figure 92. 



pallidula Mallcli. 



Mid tibia with two long apical ventral bristles, the posterior one but little 



shorter than the middle one, the anterior one reduced to a short setula : 



hypoyiiiuni as Figure 03 diversa (Kertesz). 



107. Thorax with strong acrosticlials from before suture to hind margin of 



mosonotum, three or four pairs in all; wing marked as Figure 48; 



hypopygiuni as Figure 94 geomyzina (Frey). 



Thorax with only the prescutellar acrostichals well developed, if with more 

 then the wings black, with many small w-hite or hyaline spots 108. 



108. Wings blackened or browned on costa to, or almost to, apex of fourth vein, 



the dark color becoming gradually less intense posteriorly, not extending 

 to hind margin of wing, the outer cross vein usually without a conspicu- 

 ous, separated, dark clouding 109. 



Wings with clearly defined, isolated, or connected, dark markings, and in- 

 terspersed clear areas, in front of fourth vein, the outer cross vein 

 always with a conspicuous dark mark 113. 



109. Arista almost bare grahami, new .species. 



Ari.sta plumose or at least with distinct hairs 110. 



110. Small species, about 3 mm. in length ; thorax with six series of intradorso- 



central hairs ; wings faintly clouded, the outer cross vein with a faint 



isolated cloud; hypopygium as Figure 89 laticosta (Thomson). 



Larger species; thorax with 8-10 series of intradorsocontral liairs ; wing.-* 

 conspicuously clouded 111. 



111. Longest hairs on arista about one-fourth as long as width of third an- 



tennal segment; species less than 5 mm. in length; a pale streak in 



discal cell and another pale mark in first posterior cell near middle. 



discoidalis (Kertesz). 

 Longest hairs on arista about one-half as long as width of third antennal 



segment fumipennis JIalloch. 



Longest hairs on arista as long as width of third antennal segment ; species 



at least 5 mm. in length; no pale streak in discal cell 112. 



112. A pale line along hind margin of costal vein ; abdomen pitchy black ; 



femora darker than tibiae and tarsi ; hypopygium as Figure 95. 



dichroa (de Meijere). 

 No pale line along hind margin of costal vein ; abdomen testaceous yel- 

 low, with narrow dark hind margins to tergites; legs yellow. 



nigripennis (de Meijere ~>. 



113. Wings blackish or fusctius, ^vith many small hyaline round six)ts on disk, 



and subtriangular, or oblong, hyaline spots round margins; second vein 

 farther from costa than usual, the marginal cell opposite outer cro»» 

 vein \vider than submarginal at sam^ p<jint ; one or more pairs of the 



acrostichals besides the prescutellar pair rather conspicuous 114. 



Wings hyaline, with dark markings, the pale marks on disk not consistinig 

 of numerous small round hyaline si)<)ts, and most of the margins hyaline : 

 secf>nd vein in normal position, tlie marginal cell never wider than sub- 

 marginal opposite outer cross vein ; no conspicuous acrostichals except 

 prescutellar pair 115. 



