#1
Size and behavior similar to Eristalis tenax, yet the pale basal half of the hind tibia suggests it is E. pertinax (according to description in Stubbs & Falk)
Visiting flowers of Berberis hispanica, Sierra de Cazorla, southeastern Spain, at 1600 m elevation. Picture taken 18 June 2011.
#2
E. pertinax has yellow front tarsae.
E. tenax has bands of hair on the eyes. This one is neither of them.
I would say
E. similis (because of the long stigma), but I don't know the syrphidae of Spain...
Regards Jef