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.
Medina separata
(by Janet Graham, Trawscoed, North Wales)
Medina separata
(by Janet Graham, Trawscoed, North Wales)
Gastrolepta anthracina female (by Nikk Valentine) 
Gastrolepta anthracina male (Saxifraga-Ab H Baas) 
Gastrolepta anthracina female (Saxifraga-Ab H Baas) 
Phyllomya volvulus (by Marion Friedrich, DE, Chemnitz, Hutholz) 
Phyllomya volvulus (by Marion Friedrich, DE, Chemnitz, Hutholz)
