Large Bee Fly

We've been lucky enough to have Large Bee Flies in the garden for the last two springs. I didn't know much about them until I saw them last year. Here's a bit about them:

Bombylius major (commonly named the large bee-fly or the dark-edged bee-fly) is a parasitic bee mimic fly. B. major is the most common type of fly within the Bombylius genus. The fly derives its name from its close resemblance to Bumble bees and are often mistaken for them.

B. major exhibits a unique flight behaviour known as "yawing" and plays a role in general pollination, without preference of flower type. The fly does not bite, sting, or spread disease. However, the fly uses this mimicry of bumblebees to its own advantage, allowing close access to host solitary bee and wasp nests in order to deposit its eggs. After hatching, the larvae find their way into the nests to parasitically feed on the grubs.

Photographing them is pretty difficult as they move so fast! 

And a short video:

We've got a colony of Mining Bees in the garden so they're probably parasitising these.