Markus,

It is not my intention to sound rude; however, the black on that animal looks pretty dark for it to be a killerbee. I think what you have there is a high quality citrus bumblebee. Were there any other bumblebees in the clutch to compare it to?

Don't get me wrong; it is a gorgeous animal regardless of whether it is a killerbee or a bumblebee. I've just yet to see a killerbee with such dark pattern on it, whereas I've hatched several bumblebees that have been almost white when they emerged from their eggs, similar to this one.