In Britain there are four species of bee-fly in genus Bombylius, including perhaps the recording scheme’s
most familiar fly: the Dark-edged Bee-fly Bombylius major.
The Dark-edged Bee-fly looks rather like a bumblebee, with a long, straight proboscis that it uses to feed on nectar from spring flowers such as primroses and violets. It is on the wing in the early spring, when it can often be seen in sunny patches. In flight, it is even more like a bee as it produces a high-pitched buzz. This species is common, but the Heath and Mottled Bee-flies, are classified as Priority Species in the UK Biodiversity Action Plan.
Looking like a bee, the Dark-edged Bee-fly has yellowy-brown hair on its body, long spindly legs and a long proboscis. The wings have dark markings along their leading edges, hence it's common name. There are actually several species of bee-fly in the UK, which can be very difficult to tell apart; the Dark-edged Bee-fly has a dark edge, and while others have more or less plain translucent wings. It is also the largest and most common.(link)