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Posted by Christine Devillers on 01-09-2009 15:42

This Cylindromyia was about 11 mm (Belgium, 31-08-2009).
Long apical scutellar bristles
Abdomen without discal bristles
Tergite 2 ventrally without bristles
Is it a female of Cylindromyia brassicaria ?

Edited by Christine Devillers on 03-09-2009 17:38

Posted by ChrisR on 01-09-2009 15:58

It looks like it has a postero-ventral bristle on the hind tibia so C.brassica would be ruled out ... maybe C.intermedia?

Posted by Christine Devillers on 02-09-2009 11:44

Thanks,
I've found this female in an old quarry (dry and warm). I had excluded intermedia because I thought that the bristles on hind tibia were not postero ventral, but postero-dorsal like in this post
http://www.dipter...d_id=11004.
On another post about intermedia, I've seen that basal scutellar bristles are missing. Does the following pictures help to see this feature ?

Posted by ChrisR on 02-09-2009 11:55

I have just been keying out a bunch of French Cylindromyia in Mesnil (very hard work) but if I remember correctly C.intermedia should just have strong, diverging subapicals and weak, crossed apicals (so no basals) - but this is also true of quite a few species. Mesnil splits C.intermedia from them using the presence of a small pd bristle on the mid-tibia in addition to the 2 pv bristles ... another very tricky feature to locate.

The pv is very hard to make out on most photos but I think it is present on this one. On specimens I usually do it the "easy" way and just look along the length of the hind tibia and if I see bristles radiating on all 4 sides then it has a pv and if it only has them on 3 sides then it doesn't ;)

Edited by ChrisR on 02-09-2009 11:56