Diptera.info

Posted by jck on 04-05-2019 12:50

I am trying to key this one and I would like an expert opinion on the pterostigma: is this one dark and clearly delineated (B. anglicus) or light and not clearly delineated? Personally I would choose dark but my experience of these flies is very limited. The fly is a male, 7-8mm long (measured), found dead. Am happy to post other photos if necessary. City park, Apeldoorn on 30/04/2019.

James

Edited by jck on 04-05-2019 12:51

Posted by Zeegers on 04-05-2019 14:57

Anglicus is quite unlikely at Apeldoorn. Can you check the front tibia ? Sure it is not leucopterus ?

Theo

Posted by jck on 04-05-2019 16:08

What am I supposed to look for on the front tibia - not mentioned in the keys I have?

Bibio anglicus does occur near Apeldoorn - you approved this one in 2017:

https://diptera.info/forum/viewthread.php?forum_id=5&thread_id=79013

It's on Waarneming as -

https://waarneming.nl/waarneming/view/137308208?

I also have a record from 23/04/17 (4 females) and 01/05/2018 (3 females). All 3 records can be found on Waarneming.nl (all with photos). They all come from the same place. The dead male in my post is about 1 km away in a straight line.

James

Edited by jck on 04-05-2019 16:12

Posted by Zeegers on 04-05-2019 17:04

leucopterus has the first tibia slender and the inner spur about as long as the outer one. In other Bibio, the inner spur is much shorter.

Theo

Posted by Zeegers on 04-05-2019 17:05

as for the other records, these are from “lowland”-side of Apeldoorn, the only part I’d expect anglicus.

Theo

Posted by jck on 05-05-2019 06:14

As I said, I didn't know the tibia was so important so I didn't pay much attention to it when taking photos. This is the best one. I see what you mean about Apeldoorn - there is a big difference between the west side and the east side.

James

Posted by jck on 07-05-2019 08:22

Record this one as possible B. anglicus? Or B. leucopterus? Or forget about it....

James

Posted by Zeegers on 07-05-2019 17:49

I’d need a lateral shot of tibia 1....

can’t assess the spur from this angle

Theo

Posted by Zeegers on 07-05-2019 20:42

In male anglicus, costal cell is pretty brown

So this should be leucopterus. But still, would be nice to have a better view of the front spurs.

Theo

Posted by jck on 09-05-2019 06:03

#10

I'll settle for a possible B. leucopterus - the last details aren't visible on any of the photos. Thanks for all your help.

James