Here's the fly I use to imitate the E. danica emerger - nothing fancy, quite simple really, but very effective and very durable!
Thread: UNI 8/0 or Gordon Griffith 14/0.
Tail: Three fibres from an ostrich feather.
Abdomen: Natural seal's fur.
Thorax: CDC dubbing and CDC in a dubbingloop in open turns over CDC-thorax.
Simple and deadly :-)