DIPTERA > BRACHYCERA | Higher Diptera

MUSCOMORPHA > SCHIZOPHORA > Acalypratae > Tephritoidea > Platystomatidae (2 species)

 A small family of picture-winged flies represented in Britain by just two species. 

Platystoma seminationis

A distinctive, relatively small (5-7mm) species with a greyish-brown, heavily patterned dark-mottled body, large reddish- brown eyes and dark translucent wings covered with numerous white markings. The general appearance is similar to the sciomyzid marsh fly Coremacera marginata, except that species is a little larger and slimmer with longer legs and long projecting antennae.

It is commonly known as the Speckled Semaphore Fly, but also the Dancing Kiss Fly due to their interesting mating behaviour, which involves some dance-like movements followed by the pushing together of their large probosces.

Adults are mainly seen on low vegetation in shady woodland or scrub, usually from mid-May to early August.

Given that this species is supposed to be relatively common and widespread, as well as being distinctive and easily recognisable, I was very surprised to note that the last Dorset records go back to 1998.

Rivellia syngenesiae (not yet featured)

Smaller than the previous species, but just as distinctive in its own way. Rivellia syngenesiae has a very different appearance, rather similar to the Ulidiidae species Herina frondescentiae and possibly some tephritids in the Urophora genus.  

It is sometimes referred to as the Small Semaphore Fly.

Unlike Platystoma seminationis, this species is far more likely to be found in damp or marshy areas, particularly where Greater Bird's-foot Trefoil is growing, than in more wooded areas. Adults are most active during June and July when they may be observed waving their wings in a similar manner to some Herina (Ulidiidae) or Sepsis (Sepsidae) species.

I'm not sure there's much relevance in comparing these two stablemates in terms of recorded sightings, but it's interesting to note that Rivellia syngensiae is by far the most frequently seen with an almost 4.5:1 ratio nationwide (672 v 154), which is pretty similar to the Dorset figures (33 v 6).

July 24