#3
Yes, I agree with John and I'd go for
Phytomia natalensis (Macquart, 1850). That's a really wonderful picture. The species, althought widespread in the Afrotropics, has not previously been recorded from Senegal, so that's a new country record too.
#5
Would you be prepared to post this photograph to
http://www.syrphi...? Ask Bastiaan if he'd link it to the
Phytomia natalensis file and add Senegal to the database (if he can't add it to the database, let me know and I'll write him a new file to update it).