(As usual, the "disclaimer" is relevant!!)
I photographed these on the 29th February. The larger one was about the size of a bee.
Bee flies are believed to be helpful pollinators and the larvae of many bee flies are alleged to parasitise the eggs or larvae of other insects, possibly those of grasshoppers and locusts.
Probably male and female in this shot.
Bombyliidae have a distinctive veining in the wing. I have another shot that shows this, but it might not reproduce very well after severe cropping.
The plant the bee flies are feeding on is Tanacetum parthenium (Feverfew) a member of the Asteraceae family. Parsley in the background!