Thread subject: Diptera.info :: Chrysotoxum sp.?

Posted by Maik Hausotte on 06-06-2020 11:06
#1

Hello,
is this fly a Chrysotoxum species ?
Thanks for your help,
Maik

Photo: Leipzig, Saxony/Germany, 20.05.2020

Posted by Sundew on 06-06-2020 23:39
#2

Chrysotoxum it is, and all the keys (e.g. https://books.goo...BXoECAkQAQ) beginn with length comparison of the three antennal segments - hopeless in your pictures. But there are not so many species that have (a) a black abdomen with yellow bands of equal width on (b ) tergites 2-5 and (c) the yellow bands do not reach the margin. We arrive at C. festivum and C. vernale. As the yellow bands are straight with the outer ends curved, C. festivum seems to be the better candidate. In this case, the femora 1+2 should be completely yellow, whereas C. vernale has homogeneously straight to slightly curved bands and femora 1+2 with black bases (there is a mistake in Steven Falk's description who writes that tibiae 1+2 have black bases). So, by overall appearance I tend to C. festivum!
This literature is also recommended: https://www.biodi...y-2015.pdf. Of course, it does not cover all of our species, but it helps to learn a lot.
Regards, Sundew

Edited by Sundew on 06-06-2020 23:41

Posted by Maik Hausotte on 07-06-2020 20:00
#3

Thank you for the wonderful derivation and the great literature sources. Best regards, Maik