Confidence: I'm as sure as I can be.
Notes: Large caddisfly (2.5cm) of the genus Phryganea. It could be either P. bipunctata or P. grandis, I have been told that differentiation by markings is considered unreliable. Genital insepection is necessary. Many were observed on the rocky fringe of a small upland lake, one had very badly formed wings as can be seen in the 2nd pic.