Thread subject: Diptera.info :: Tiny black fly

Posted by Susan R Walter on 28-01-2007 22:55
#1
As ever, with tiny shiny black flies I think Lonchaeidae, but they never are. Also wondered about Aulacigastridae.

4mm, from 21 November 2006, east London cemetery park.
Edited by Susan R Walter on 28-01-2007 22:57

Posted by Susan R Walter on 28-01-2007 22:55
#2
Another view.

Posted by Paul Beuk on 29-01-2007 08:32
#3
This is an agromyzid...

Posted by Susan R Walter on 29-01-2007 14:18
#4
Ta Paul - I knew it wouldn't be anything like what was coming to my mind.

Posted by Susan R Walter on 29-01-2007 22:45
#5
Paul

How could you tell it was an Agromyzid from these images? I have gone back to the specimen and my key to British Families of Diptera (Unwin) and have noted:

a) post-verticals long and divergent
Cool 3rd antennal segment rounded
c) sub-costa merges with Vein 1 (completely missed that one first time round, and it's actually the most obvious of the characters on such a small dark flySad)
d) lower orbitals incurved (damned hard to see the little blightersShock - and certainly not from the photo)

Without being able to see all 4 of these characters, how did you know?