The Dotted Beefly, Bombylius discolor is not uncommon on the coast, for its main host appears to be the mining bee, Andrena flavipes.
Otherwise it is very uncommon throughout the rest of the British Isles.
Gravid females coat their eggs in sand and flick their eggs into the nests of these mining bees, where the larvae develop to parasitise the bees or their larvae.
They are easily distinguished from the very common B. major, which also occurs here, by the obvious spots on the wings (though a photo may be needed for this)
However, I am reliably corrected that this bee on the Draba is Lasioglossum calceatum, another early ground-nesting solitary bee which may also be parasitised by the Beefly.