Roger,...
The Italians call this mayfly "Arenanna."
(cropped/resized version of photo received from Douglas)
Douglas-
Your mayfly is Oligoneuriella rhenana, the only Italian species of family Oligoneuriidae (Bushlegged Mayflies). Here is an
illustration of it by Paul Troël from
http://troel.free.fr/PL10.htm.
