Thread subject: Diptera.info :: Siphona geniculata [Tachinidae]

Posted by Susan R Walter on 10-02-2007 22:02
#1

Hi Chris :) - another Siphona. I've had a go at keying it and think it is S geniculata again, but the head has been scratched to get there.

5mm, from 3 September 2006, east London cemetery park.

Front femur wider than 3rd antennal segment. 4 psdc (I think - they really are not that easy to spot), 2 dc on margin of tergite 2, tegula appears darker than basicosta again though. Ground colour is an unappealing dirty grey beige. Hairlets under frontal bristles to about halfway down cheek (perhaps slightly less than halfway).

Posted by Zeegers on 11-02-2007 11:10
#2

Looks and sounds like S. geniculata.
But difficult to tell (always in Siphona), and would need a headshot in profile.


Theo

Posted by Susan R Walter on 24-02-2007 17:31
#3

Does this help?

Posted by Susan R Walter on 24-02-2007 17:32
#4

Another close up.

Posted by Susan R Walter on 24-02-2007 17:33
#5

And another close up.

Posted by Zeegers on 25-02-2007 20:36
#6

Yes and no.
It makes me doubt whether it is geniculata. Could be cristata.
As always, impossible to tell from picture in Siphona.

Theo

Posted by Susan R Walter on 25-02-2007 22:45
#7

Is it worth pursuing? What should I be looking for? Is it the hairlets under the frontal bristles - they were not easy to count on this specimen, and I did think they could have been a bit meagre. I've got 4 Siphona from this site, all of which I think are S geniculata. I thought S cristata could be distinguished from S geniculata because S cristata does not have dorsal marginal bristles on tergite 2 and S geniculata (and this specimen) does?