Here's the fly I use to imitate the E. danica emerger - nothing fancy, quite simple really, but very effective and very durable!

Pattern:
Thread: UNI 8/0 or Gordon Griffith 14/0.
Tail: Three fibres from an ostrich feather.
Rib: GSP-thread.
Abdomen: Natural seal's fur.
Wingcase: Polyyarn.
Thorax: CDC dubbing and CDC in a dubbingloop in open turns over CDC-thorax.

Simple and deadly :-)