Check out the excellent video from T. Flagler which I found on Chi Wulff’s blog. This style of midge works exceptionally well in Ireland when tiny black flies are on the water in May and June.
He ties this fly on a size 22 but I find it works all the way up to size 14 (we must have bigger midges here in Mayo!). The colour combination can be varied too. An olive midge has worked well for me in the past and I have a red version which has still to be tried but should do the business.
i also vary the wing material and use white polypropylene sometimes. This material lies much flatter and so gives a different outline tot he fly but it seems to work equally well.
You can rattle these flys out in no time at all and in a wide range of colours to meet local conditions. I recommend you have a few in the box, they are a steady producer of browns.