Thread subject: Diptera.info :: Eristalis pertinax?

Posted by Trond on 11-07-2011 08:33
#1

Correct? From S. Norway 07.06

images55.fotki.com/v608/photos/6/8126/9878812/IMG_2862_Eristalispertinax-vi.jpg

Posted by Trond on 15-07-2011 10:51
#2

Decided this had to be E. pertinax

Posted by Jan HC Velterop on 15-07-2011 11:17
#3

I don't belief: both fore tarsus are dark, not yellowish as is the exclusive character of E. pertinax; the small stigma in the wing points more to E. nemorum.

Posted by tristram on 15-07-2011 11:32
#4

I was going to suggest E. similis on the basis of these passages from Stubs and Falk (British Hoverflies):

E. tenax: "... differs from pertinax in the presence of a dark front tarsus, and from both pertinax and similis by the stripes of dark hair down the eyes, the almost completely dark hind tibia with long hairs on the dorsal and ventral surfaces, and the very broad black face stripe."

E. Pertinax: "... has an entirely orange front tarsus (unlike [tenax and similis]) and the hind tibia is pale in the basal half (unlike tenax)."

E. similis: "... the front tarsus is black (entirely yellow in pertinax), the face is extensively dusted (tenax has a wide black facial tripe) and the hind tibia is broadly pale at the base (like pertinax but unlike tenax)."

They have E. nemorum as a synonym of E. interruptus. I will go and look it up.

Edited by tristram on 15-07-2011 11:34

Posted by Trond on 15-07-2011 11:54
#5

I got a tip elsewhere a few minutes ago too: Eristalis interrupta. Wich I guess is the same as E. nemorum even if tristram spelled it different...?

Posted by tristram on 15-07-2011 12:11
#6

For E. interruptus Stubbs and Falk say: "Stigma reduced to small spot before tip of Sc."
What this means is, if you look at the small dark patch on the leading edge of the right wing, the vein that runs down parallel to the leading edge should reappear below the patch before it joins on to the leading edge. In the above image I don't think it does, which suggests it is not interruptus.

Edited by tristram on 15-07-2011 12:14

Posted by tristram on 15-07-2011 12:20
#7

This recent thread suggests that E. similis is rare in Norway: http://diptera.in...d_id=39805

Maybe we should wait for an expert to give their opinion.

Posted by Trond on 15-07-2011 12:50
#8

I will let it be Eristalis interrupta (dont know why its called interrupta instead of interruptus in the norwegian website for registring insects etc) for now, and hope for more comments. I can see what you say about the stigma I think...

I didnt get any pics from other angles, so I cant see if there are any dark hairs on the eyes as in tenax...

For E. similis, the frontlegs on mine seem to be darker? Also since its so rare up here, I kinda doubt thats the one...

I'm confused, but will come back if I hear anything on the nor. website.

Posted by Trond on 15-07-2011 12:54
#9

I would say it have 'dark hind tibia with long hairs on the dorsal and ventral surfaces' so I'm leaning towards E. tenax right now... :o