---

Nick, I take your point about better optics but actually I was thinking more of the field guide revolution started by Peterson.

As for general/family keys, have you looked at these two:

Dipterist Forum - Key to Families (Ball) http://www.dipter...ptera.html You may need to become a member but highly recommended.

FSC AIDGAP key - A Key To The Families of British Diptera (Unwin) http://www.field-..._143_A.pdf

I particularly like Stuart Ball's key, very nicely illustrated and as clear and simple as these things are ever going to be.

best of luck

Tim