Diptera.info

Posted by Urs on 19-01-2008 10:27

the male of this pair shows a more silvery face. Also Eristalis pertinax?

Foto: Switzerland, Wattwil SG, 750m NN, 19.August 07

Thank you for any help

Regards
Urs

Posted by Andre on 19-01-2008 15:04

Eristalis interrupta (= nemorum). Nice capture of this copula! And what an incredible difference in size ;)

Posted by Andre on 20-01-2008 18:09

Jugorum has broad black median line over the face (interrupta has a small line, like in this case), wings with zig-zag-band.. Face of jugorum is more protruded downwards, but that may be more difficult to see from this angle.

Posted by dipdip on 21-01-2008 18:03

Yes, but it is so difficult to tell from pictures for sure ...
There are flies that don't show us - neither a zig-zag-band nor a really broad median line in the face.
Thanks for answering!

Edited by dipdip on 21-01-2008 18:05

Posted by Andre on 21-01-2008 22:06

To dipdip: the upper Eristalis looks like interrupta to me, because of the yellow base of femur 3 and very small black median stripe on the face. The lower is a clear jugorum indeed.
With these examples I must confess that the copula could be jugorum, because of the very black pterostigm. On the other hand, the median stripe of the face is very narrow.... I stick to interrupta.

Must add that I have little experience with this species, perhaps I should visit the Alps again...

Edited by Andre on 22-01-2008 02:05

Posted by Zeegers on 21-01-2008 23:15

The last picture shows very nicely the long black hairs on backside of femur 1, a typical feature of male jugorum.

Consequence: I have little doubt the last picture is, indeed, jugorum

Theo

Posted by dipdip on 22-01-2008 11:04

#10

And the upper picture shows the same strong hairs, but jellowish as it is a female. And the first picture of Urs shows a big fly with strong jellowish hairs at femur 1 on the back side.
All of them have rather long hairs on the back of their thoraxes.

Posted by Sundew on 23-01-2008 14:50

#11

Unfortunately, the copulating male does not show us his foreleg hairs. The yellow hairs of the female leg are also present in E. interrupta, as far as I see from many serious internet sources. And now the photo by Urs is in the gallery as E. interrupta, so I consider the discussion settled - ?
Sundew (still struggling with that genus, too)

Posted by jorgemotalmeida on 24-01-2008 11:00

#12

yesterday I saw two syrphids in kamasutra and it pays my attention when I realized the big differences in size like the first photo. ;) not Eristalis, though. :P

Posted by Zeegers on 24-01-2008 22:41

#13

The feature of jugorum on femur 1 is not hairs, but black hairs.
Yellow hairs at that locality are common in Eristalis, like horticola.
So yellow hairs don't count (that is, for jugorum).
And it is only valid for the male sex.

Theo

Posted by Gerard Pennards on 28-01-2008 23:43

#14

I looked at some specimens of Eristalis jugorum in my collection, and I also think the somewhat pointed snout of the animals is visible, so my idea would indeed be a pair of Eristalis jugorum!
greetings,