That's a fly you have shown me before Hans, I've tied it and fished it a few times without success, but it came to mind when looking for a pattern to imitate the heather beetles we get huge falls of in late April and into May. Tied with a shorter, fatter, dubbed body it works great for them. The tailing CdC, I think, representing the wings as the beetle furls them under its carapace. The dubbing I use is quite a bit darker for the beetle imitation. Really its the tying technique I pinched.

Cheers,
A.