That looks like it might do the job for greenfly...
Had an infuriating session a while back, where the trout were rising, but I couldn't figure out what to, and they took nothing I offered them - there was loads of fly life on the water.
Playing it back in my head later that day, and I realised that they were only coming up under trees, not out in open play. I reckon they were coming up for greenfly falling on the water.
Had a word with my mate Pete who is a seriously good fly fisher, he said quite possibly, he's known trout feed selectively on greenfly like that...
I'll have a play with this pattern, then next time I will be ready for 'em!
Andrew