Nice & sharp in-flight capture of the European honey bee. Good job holding back the white of the matilija poppy petals. Would like to have seen a bit more DOF; the anthers in front would have been brought in focus, but then perhaps the bee would not have been frozen as well.
The right edge of the petal falling off at right caught my eye. I mentally cropped 2-3 cm off the right, and 1-2 cm from the bottom, you might have a look at that.
James, this is an excellent "in flight" presentation. I agree that the pollen sac is really a plus in this instance as it adds a beautiful touch of color to the yellows in the flower.
I'm on a work monitor so I hate to bring this up as it could just be my monitor but the whites in the back petals look rather gray. Did you do any white balance testing? (Again...might just be me!)
I'd also look at cloning out the tiniest specs of flash residue (did you use flash?) I don't mind where the light hits it in long pieces but the few little "specs" could go I think.