Thread subject: Diptera.info :: Chrysotoxum intermedium?

Posted by dipdip on 17-11-2007 15:55
#1

Hello

I think it is a female Chrysotoxum, but I don't know if it was Ch. intermedium.

Could you help please?
Maja

Edited by dipdip on 17-11-2007 15:56

Posted by amalia_raluca on 17-11-2007 19:38
#2

It looks more like C. cautum to me...
Amalia

Posted by dipdip on 17-11-2007 21:20
#3

In this case the triangle at the back would be "the membranous strip on tergite 6 which divides this tergite in two parts" as Gerard Pennards described it for cautum. I have only pictures ....
Isn't cautum more hairy?

Maja

Posted by Gerard Pennards on 18-11-2007 00:24
#4

Well, in this case I agree with Maja, and I think this is a female of Chrysotoxun intermedium!
The third antennal segment is clearly longer than segment 1 and 2 together, abdominal hairs (seemingly) very short and frons yellow!
Also size and color of abdomen are different from cautum.
This is how a typical female cautum looks like:
http://www.microscopy-uk.org.uk/mag/imgmay07/chrysotoxum_cautum.jpg

The membranous strip on segment 6 I'm talking about is visible on this specimen:
http://www.evasion.it/ditteri/Chrysotoxum_cautum00.jpg
Between the more orange colored parts of tergite 6 one can see the membranous strip as a yellow line in the middle!
That's a feature only the female of cautum has!!
Greetings,

Edited by Gerard Pennards on 18-11-2007 00:27

Posted by dipdip on 18-11-2007 11:26
#5

Thank you very much for helping! I'll try hard to veryfy what you explained next year. This year I didn't find many Chrysotoxum sp.
Thanks and Regards Maja