I collected this one last sunday september 4th 2016. 10 mm (around).
France, Choisy le roi, 10 km south east from Paris center.
I tried to follow the Benson key for Tenthredinidae and it led me to Tenthredo marginella ... then on a french forum (insectes.org) I red about the difficult couple marginella/thompsoni and then I went to this paper !
Unfortunately I strictly don't understand german language ... and it's too tuff for me and google traduction ...
Well, it seems to me that the lateral side of the thorax is covered with points but on the opposite side I see clearly a yellow spot at the base of the external side of the mandible ...
So first of all, Am I right thinking about marginella/thompsoni ? And Is it possible to go further ?
Thanks in advance !!!