I’m a bit late with this one I know. When I was last out there were only a few about, compared with the previous weeks when there were thousands. The hawthorne – bibio marci – is the first terrestrial fly to grab the trout’s attention. Big and black and leggy, even a light breeze is enough to blow them onto the water in sufficient numbers. Also known as St Mark’s fly because they begin hatching on or around St Mark’s day the twenty fifth of April.