These are the hoverfly Merodon equestris and this species come in several colour morphs that mimic different species of bumblebees. The two on the picture are both of the form bulborum.
The larvae live in th bulbous roots of various species of the onion family, Alliaceae, and allied families.
They should also live in the Syrphid part of the forum where someone will move this thread =)
cheers,
Viktor