Thread subject: Diptera.info :: Small black dark winged muscid
Posted by peterbolson on 02-07-2010 11:49
#1
I'd appreciate some help with this. 7mm long from woodland ride.
Thanks
Peter
Posted by peterbolson on 02-07-2010 11:50
#2
lateral
Posted by Stephane Lebrun on 02-07-2010 18:02
#3
Sorry, I can't see the determinant characters (chaetotaxy of legs / thorax). How many post dc ? Are there prst acr ? Pre-alar long or short ? Is there a "Phaonia bristle" on hind tibia...
Posted by Stephane Lebrun on 02-07-2010 18:24
#4
I have lightened a bit the pictures for trying to see something, and it seems it has no pra and some dark marks on abdomen (+ general appearance and darkened wings), I think you can begin to search in the
Spilogona genus.
Posted by peterbolson on 02-07-2010 20:15
#5
Hi Stephane
Sorry about the photos. It is a very dark fly :)
I can't see any markings on the abdo. The eyes are bare, aristae short haired plumose. No presutural ac, 4 postsut dc. No pd seta on hind tibia.
I think the pre alar seta is present & long. Does that rule out Spilogona ? I've added a photo to try & show this in case I'm wrong - I find the setae in this area a bit difficult to sort out.
I'll carry on looking after I've had your opinion so far, if that's OK with you.
Peter
Posted by Stephane Lebrun on 02-07-2010 21:46
#6
No, I can't see any pre-alar, this is only the supra-alar. To find the pra, imagine a line running from the posterior notopleural to the first ia, then the pra should be approximatively at theintersection of the supar-alar row and of this imaginary line (see the annoted picture).
I think it could be Spilogona denigrata regarding the frons width, the strong infuscated wings and blackish halters, however it is just a guess as this is a very difficult genus (even under lens) with many many species in the Northern areas.
Edited by Stephane Lebrun on 02-07-2010 22:03
Posted by peterbolson on 02-07-2010 23:07
#7
Hello Stephane
Thank you so much for that extremely helpful explanation.
I have had another look at it & I was wrong about the lack of markings. There are large squarish dark spots on tergites 3 & 4 with a grey dusted line between. I could also see 2 hairs near the insertion of the post np and pvs on the basal half of the hind femur.
So perhaps you are right about S.denigrata, although Gregor says this is mainly in mountains alongside streams. This was in a wooded area near a small river and there are lakeland hills a mile or so away - I wouldn't exactly call them mountains :)
Once again many thanks for your help & advice.
Regards
Peter