Let's try with this one as well: https://www.jstor.org/stable/30152970?seq=1 https://www.journals.uchicago.edu/doi/10.1086/physzool.2.4.30152970 Thanks in advance. Ximo -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.nottingham.ac.uk/pipermail/syrphidae/attachments/20201127/d6a89cf5/attachment.html>