This is one of the largest upwinged flies of Europe and Britain. Fly fishermen call it Large Summer Dun/Spinner. This insect is not well known as a Green Drake or Blue Winged Olive, but it is present in decent numbers in many lakes and rivers. The nymphs are agile darters and can be found in slow parts of the rivers and near banks of the lakes. They crawl ashore to hatch. They are interesting to flyfishermen because they do it just a few centimeters outside of the water, and many duns fall in. Fish easily grab this handsome source of food. Later, as the spinner, Siphlonurus female come back to lay eggs dipping into the water, again in fish-eye focus.
Large number of Siphlonurus nymph preparing to hatch
The hatch is on!
Dun
Large number of Siphlonurus nymph preparing to hatch
The hatch is on!
Dun