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Hi,

I've been asked to explore the syrphid fauna of rot holes in a German park. The rot holes there are usually several metres up in the trees. Further, it is not allowed to destroy the habitat, i.e. cut the trees or remove material from the rot holes (there is a population of Osmoderma eremita...). Does anyone have experience with a trap designed for colleting flies from rot holes which is good esp. for syrphids?

Dieter