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Hi,
Yesterday (a very warm day) I saw many small dark flies quickly running on some erratic boulders that were placed along a park way. While running, they waved their wings just like in the video by Rui Andrade (https://www.youtu...bZG15xbHRk). When two met, they closely circled each other and jumped on and off at high speed. Very short phases of resting made taking pictures difficult. The darkened wings were conspicuous.
I think they might be Periscepsia carbonaria, the species is said to occur in the Berlin region. Experts’ opinion is appreciated, however! Thanks in advance, Sundew