1) "Metasternum at least narrowly sub-membranous in the middle, usually very widely so" (Note: Although this character is not visible in your photos, the alternative choice of couplet 2) here leads to inconsistent results...in addition, only Polybiomyia have a "complete post-metacoxal bridge", but they all have a much shorter frontal prominence);
8) "Antennal process at least as long as the first antennal segment" ;
9) "Second abdominal segment strongly constricted" ;
10) "Abdomen reddish" ;
11) "First abdominal segment yellowish the basal half or more" (and this is not tricolor!) ;
12) "Dark markings of the head and thorax black"......vittipes