Thread subject: Diptera.info :: Chrysotoxum fasciolatum

Posted by Jef Hendrix on 26-07-2013 12:35
#1

A Chrysotoxum from the eastern Pyrenees near Prades (France) at an altitude of +-1500m.
12/07/2013
Can anyone help?

Jef

Edited by Jef Hendrix on 29-08-2013 08:02

Posted by Jef Hendrix on 26-07-2013 12:36
#2

2

Posted by Sundew on 27-07-2013 13:35
#3

Indeed a female Chrysotoxum. With the key http://web.archiv...x_key.html, I arrive at Chrysotoxum cautum, as the third antennal segment seems to equal segments 1 + 2. Unfortunately, I cannot see the character: "female: unique among European Chrysotoxum in possessing a longitudinal, median, membranous strip on abdominal tergite 6, which effectively divides this tergite into two parts". Also the scutellum is unusually dark. So here I am at my wits' end!
Regards, Sundew

Posted by Gerard Pennards on 27-07-2013 17:41
#4

It's a female Chrysotoxum fasciolatum... :-))

Posted by Sundew on 27-07-2013 18:36
#5

Ah - in this case "Wing: front margin yellowish with a distinct dark spot in the top half; abdomen elongate; large species: 13-17 mm" is a good description in the key. As to the antenna, segment 3 has to be longer than 1 + 2 to get to Ch. fasciolatum. So my estimation was wrong awkward.
Good to have true experts here!

Posted by Jef Hendrix on 29-08-2013 08:06
#6

Thanks Sundew and Gerard!