76 R. W. CROSSKEY 



2 Scutellum with a total of four or more pairs of marginal setae (one or more pairs of 



lateral setae present in addition to the basals, subapicals and apicals) ; apical 

 scutellar setae divergent and usually inserted above the level of the subapical setae; 

 subapical scutellar setae close together, distance between their bases very much less 

 than distance from either to its corresponding basal corner of the scutellum. 

 Second costal sector bare ventrally . . XANTHOPTEROMYIA Townsend 



- Scutellum with a total of three pairs of marginal setae (lateral setae absent) ; apical 



scutellar setae crossed and horizontal; subapical scutellar setae widely separated, 

 distance between their bases much greater than that between either and its corres- 

 ponding basal corner of the scutellum. Second costal sector haired ventrally . . 3 



3 Head with a series of 5-7 pairs of proclinate orbital setae in both sexes (Text-fig. 57). 



Head in facial view with the eyes converging ventrally so that the facial region is 

 narrower than the frons and contracts towards the epistome (Text-fig. 71). Anten- 

 nae exceptionally small and inserted at a level far below the eye middle (Text-fig. 57) 



HALYDAIA Egger 



- Head without such a series of proclinate orbital setae, at most only with the normal 



two pairs in $ and sometimes also in o"- Head in facial view with the eyes diverging 

 ventrally (e.g. Text-fig. 70) or with subparallel inner margins, the facial region 

 therefore not contracting and usually widening towards the epistome. Antennae 

 of varied size, usually not inserted very much below the level of the eye middle . 4 



4 Abdomen with strong median discal setae on T3 and T4 and with median marginal 



setae on Ti + 2 . . . . . . . . . . . . 5 



- Abdomen without median discal setae on T3 and T4 and without (or with very weak) 



median marginal setae on Ti + 2 . . . . . . . . 7 



5 Abdomen long, slender and fusiform; Ti + 2 not excavate. Subapical scutellar setae 



not widely separated, distance between their bases less than that between a sub- 

 apical seta and its corresponding basal corner of the scutellum. Antennae large, 

 their length subequal to or greater than the horizontal diameter of the eye and the 

 third segment four or five times as long as the second segment. Frons broad and 

 with two pairs of proclinate orbital setae in both sexes. [Species with abdominal 

 pattern as in Torocca munda and with wing veins R x and R i+i (usually also base of 

 Cwj) extensively setulose] .... POL YGAS TR O P TER YX Mesnil 



- Abdomen subovate; Ti + 2 excavate to its hind margin. Subapical scutellar setae 



widely or very widely separated, distance between their bases slightly or very much 

 greater than that between a subapical seta and its corresponding basal corner of 

 the scutellum. Antennae small or of moderate size, shorter than the horizontal 

 diameter of the eye and with the third segment not more than about three times as 

 long as the second segment. Frons of 5* much narrower than that of $ and without 

 proclinate orbital setae ........... 6 



6 Fore coxa with short fine uniform hair on the whole inner anterior surface. Three 



post ia setae. Arista short-plumose (Text-fig. 38). Vibrissae inserted about on a 

 level with the epistomal margin. Pteropleural seta absent. Scutellum with a 

 pair of recumbent discal setae .... THELAIRA Robineau-Desvoidy 



- Fore coxa bare on most of the inner anterior surface. Two post ia setae. Arista 



pubescent. Vibrissae inserted at a level conspicuously above the epistomal (oral) 

 margin (Text-fig. 70). Pteropleural seta present (but not very strong) 



PROSHELIOMYIA Brauer & Bergenstamm 



7 Mid tibia with two ad setae. Three post dc setae. Pleural regions of the thorax with 



abundant pale yellow hairing. Notopleuron with pale yellow hair. Eyes very 

 large and frons and gena correspondingly reduced (vertex about half the width of 

 one eye seen from above and depth of the gena less than the width of the third 

 antennal segment). Second costal sector almost as long as the first sector and 

 much longer than m-cu. Bend of vein M moderately abrupt and m-cu nearer to the 



