Identifying slim, black tachinids with grey dusting

I always seem to have difficulty identifying the slim black&grey tachinids in the tribe Blondeliini and Phyllomya volvulus in photos. This mini article is a work in progress but should give some clues and rules of thumb that might be useful:

  • Phyllomyia volvulus: orange/yellow wing bases/calyptrae; long & strong abdominal bristles, often longer than one segment or the width of the abdomen; head tall in profile with long receding face, frons about 1/3 the width of the head – never narrow even in males.
  • Gastrolepta anthracina: abdomen is slightly shorter than the head+thorax, less heavily bristled; head proportionally quite wide compared to the thorax with a long, sloped frons, giving a “streamlined” profile.
  • Medina sp.: head relatively small when compared to the thorax, with frons narrow; wings usually very broad; thorax and abdomen more heavily dusted; abdomen appearing quite “hairy” with weaker bristles than in Phyllomya but still quite heavily bristled, unlike Gastrolepta.