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 Syrphid? --> Scaeva selenitica? Or Scaeva dignota?
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| undina-bird |
Posted on 22-06-2011 23:33
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Member Location: Russian Fed., St. Petersburg Posts: 7 Joined: 22.06.11 |
Hello all, Pls help to ID this hoverfly. Date: June 17, 2011 Location: 30 km south of St. Petersburg, Russian Fed. Habitat: garden Thanks! undina-bird attached the following image:  [186.97Kb] Edited by undina-bird on 23-06-2011 05:56 |
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| Stephen R |
Posted on 22-06-2011 23:40
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 Member Location: Clitheroe Lancashire UK Posts: 2396 Joined: 12.06.09 |
I think it is Scaeva selenitica (female) |
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| undina-bird |
Posted on 22-06-2011 23:48
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Member Location: Russian Fed., St. Petersburg Posts: 7 Joined: 22.06.11 |
Stephen R, thank you! |
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| blowave |
Posted on 23-06-2011 02:46
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 Member Location: LINCOLN, UK Posts: 3151 Joined: 27.06.07 |
The spots look to reach the lateral margins, that would make it Scaeva dignota? Janet http://cubits.org... |
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| undina-bird |
Posted on 23-06-2011 06:19
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Member Location: Russian Fed., St. Petersburg Posts: 7 Joined: 22.06.11 |
blowave, thank you for the opinion! I have no keys for Diptera, I don't see much difference between the two and now I really don't know... Is it important that on all photos of Scaeva dignota I found, dignotas have completely or almost completely light-yellow abdominal side of the body (while the one on my photo has large black spots on it)?http://denbourge.free.fr/Insectes_diptera_syrphidae_Scaeva_dignota.htm http://www.galerie-insecte.org/galerie/pays-29-syrphidae.html http://www.diptera.info/forum/viewthread.php?thread_id=12115&pid=57203 http://macroid.ru/showphoto.php?photo=45782 (I understand that some may have mistakes, of course...) |
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| blowave |
Posted on 23-06-2011 13:33
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Member Location: LINCOLN, UK Posts: 3151 Joined: 27.06.07 |
Mark van Veen keys doesn't mention yellow at the edges of the abdomen for S. dignota. S. selenitica spots do not reach the sides where for S dignota they normally do reach the margins. Search for Scaeva dignota on this site, many other sites are not reliable. You might post this in the syrphidae forum where it will get the attention of syrphidae experts. http://cubits.org... |
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| undina-bird |
Posted on 25-06-2011 01:15
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Member Location: Russian Fed., St. Petersburg Posts: 7 Joined: 22.06.11 |
Thank you! |
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| Stephen R |
Posted on 28-06-2011 13:41
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Member Location: Clitheroe Lancashire UK Posts: 2396 Joined: 12.06.09 |
It seems to me that the spots do not quite reach the edge of the tergites - there is a black line beyond them. According to Fauna Eur. S. dignota should not be found around St. Petersburg. Perhaps an expert will help  Stephen. |
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| blowave |
Posted on 28-06-2011 13:46
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Member Location: LINCOLN, UK Posts: 3151 Joined: 27.06.07 |
It's really quite difficult to tell if the spots do or don't reach the margin. I wonder if undina-bird could post a closer crop of the pic viewing from the top? The angle from underneath might be giving a false impression. I think if it could be seen for sure an expert might have replied by now. http://cubits.org... |
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| undina-bird |
Posted on 28-06-2011 21:46
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Member Location: Russian Fed., St. Petersburg Posts: 7 Joined: 22.06.11 |
> I wonder if undina-bird could post a closer crop of the pic viewing from the top? The angle from underneath might be giving a false impression. This one the most "from the top" view I've got. Here is original size. Hope this helps. There are black lines, though very thin ones? Unfortunately, there is no S.dignota in the gallery on this site to compare, only S.selenitica http://www.diptera.info/photogallery.php?album_id=49&rowstart=780 Identified as Scaeva dignota — http://www.diptera.info/forum/viewthread.php?forum_id=7&thread_id=12115 undina-bird attached the following image:  [154.37Kb] |
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| blowave |
Posted on 28-06-2011 22:01
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Member Location: LINCOLN, UK Posts: 3151 Joined: 27.06.07 |
The spots certainly look to reach the side margins to me! Look at these.. http://diptera.in...ost_126629 http://diptera.in...post_50398 undina-bird, you can make the links clickable by highlighting the link then click on the icon at the bottom of the post which is a circle with an arrow.
http://cubits.org... |
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| Menno Reemer |
Posted on 29-06-2011 09:13
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Member Location: Posts: 343 Joined: 10.06.04 |
In certain specimens of S. selenitica the yellow maculae also reach the side margin, so the character is not reliable for distinguishing these species. It can only be used as a first indication: in S. dignota they always reach the side margin, in S. selenitica only in some specimens. While males can be quite easily distinguished by the angle between the eyes on the frons, distinguishing thhe females is much harder. You need to take measurements of the width of the face relative to the width of the head, in frontal view. I'm afraid this is not possible with these pictures. My gut feeling, for what it's worth, says this is S. selenitica... |
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| undina-bird |
Posted on 30-06-2011 19:28
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Member Location: Russian Fed., St. Petersburg Posts: 7 Joined: 22.06.11 |
Thank you very much to all! Menno Reemer, that's right, I don't have frontal view. Thus, let it be Scaeva selenitica. |
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