Thread subject: Diptera.info :: Syrphid? --> Scaeva selenitica? Or Scaeva dignota?
Posted by Menno Reemer on 29-06-2011 09:13
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...