A bee-like (Black and yellow)
      fly on a blue flower of Chicory

A bee-like fly

A bee-like fly on a
      yellow flower of dandelion
On dandelion

( Syrphidae, Eupeodes luniger )

This harmless fly looks like a dangerous bee for birds and for humans. It is a specific protective (mimic) colouring. Syrphidae can hang in air like hummingbirds.