TACHINIDAE O I' AUSTRALIA 93 



times absent) and directed at least slightly upwards, if strong and horizontal 



then weaker than subapical scutellar setae ....... 3 



Eyes haired (hairing long, dense and very conspicuous) ..... 4 



Eyes bare (a few very minute hairs sometimes visible under high magnification) . 13 



Head without definite reclinate orbital setae. Frontal region bulbously convex 

 and with very reduced frontal setae (fig. 21 in Malloch, 19296). Head ground 

 colour bright orange-yellow with blackish ocellar triangle. Legs unicolorous 

 orange-yellow. Abdomen thickly greyish white pollinose with a pattern of 

 black spots. Each side of venter of abdominal tergites 3 and 4 in £ with a 

 dense hair fascicle ARRHENOMYZA Malloch 



Head with one or more pairs of strong reclinate orbital setae. Frontal region not 

 bulbously convex (distinctly flattened when seen in profile) and with well developed 

 frontal setae. Head ground colour not so. Legs black or brownish black 

 (except in Zebromyia). Abdomen without such pattern. <$ without dense hair 

 fascicles on abdominal venter ......... 5 



Facial ridges very wide and covered with several irregular rows of small strong 

 setulae (setulae only slightly increasing in size towards front edge of ridge). 

 Parafacials haired at upper ends immediately below lowest frontal setae. 

 Prescutum and scutum each with a transverse row of four small black spots 

 anteriorly (distinct against the yellowish grey pollinose background). Abdomen 

 conspicuously patterned, T3-T5 greyish yellow pollinose with dark marks in 

 form of a pair of wide blackish or dark reddish brown triangles on T3 and T4 

 and a pair of small round black spots at tip of T5. Head with reddish ground 

 colour and chequered silvery white pollinosity that appears to shift with direction 

 of light. Legs reddish yellow ZEBROMYIA Malloch 



Facial ridges bare or setose ; if setose then with a row of strong setae on front edge 

 and only one or two inconspicuous setulae outside of the main row. Parafacials 

 either completely haired or completely bare. Prescutum and scutum without 

 such pattern. Abdomen without such pattern. Head not so. Legs black 

 or brownish black ........... 6 



Parafacials completely haired. Ocellar setae absent. Always fewer than four 

 sternopleural setae. Lateral scutellar setae absent (except in occasional specimens 

 of Polychaeta) ............ 7 



Parafacials bare. Ocellar setae present or absent. Sometimes four stpl setae. 



Lateral scutellar setae present ......... 9 



Dorsum of abdomen shining black or very dark red-brown except for last visible 

 tergite (T5) which is thickly coated with uniform whitish pollinosity (pale last 

 abdominal segment therefore strikingly contrasting with the rest of the abdomen) 



EURYGASTROPSIS Townsend 



Abdomen not so, ground colour reddish to blackish with thin whitish pollinosity 

 (sometimes appearing patchily distributed) on all tergites, no segments shining 

 and last segment not contrasted in colour with remainder of abdomen ... 8 



Arista thickened on more than its basal half, sometimes on most of its length; 

 second aristal segment normally at least 2-5 times as long as broad. Pollinosity 

 of abdomen tending, to naked eye, to appear more conspicuous anteriorly on 

 segments than elsewhere or to appear rather chequered. Smaller forms, length 

 8-1 1 mm TRITAXYS Macquart 



Arista only thickened on its basal half or less; second aristal segment not more 

 than twice as long as broad. Pollinosity of abdomen tending, to naked eye, 

 to appear as a very thin but evenly distributed bloom. Larger forms, length 



12-16 mm POLYCHAETA Macquart 



[This genus is only very doubtfully distinct from Tritaxys] 



Four sternopleural setae (2 + 2). Second aristal segment distinctly elongate 



(about three times as long as broad or more) ...... 10 



