Mayfly (Ephemeroptera)

Mayfly (Ephemeroptera)

Observation - Mayfly (Ephemeroptera). Description: A medium-sized mayfly found on a window. Can anyone help with an ID, please? Edit: Changed to match Martin's ID. Many thanks.

A medium-sized mayfly found on a window. Can anyone help with an ID, please?
Edit: Changed to match Martin's ID. Many thanks.