Fever Fly (Dilophus febrilis)

Fever Fly (Dilophus febrilis)

Observation - Fever Fly (Dilophus febrilis). Description: For a short time the Rosebay Willowherb was covered in these small, black flies. Anyone know what they are, please? Edit: 3rd photo added where you can just see the ring of spikes on the tibulae. This fly was on a caravan adjacent to the Willowherb. Than

For a short time the Rosebay Willowherb was covered in these small, black flies. Anyone know what they are, please?
Edit: 3rd photo added where you can just see the ring of spikes on the tibulae. This fly was on a caravan adjacent to the Willowherb. Thanks to Steve for the pointer.