Derudas has a website at OriDavid. His diagrams for the butterfly are at: http://digilander.libero.it/oridavid/tecnicafarf.htm. By the way, the butterfly on his website is called "Farfalla." I guess that is Italian for butterfly!
Here is a picture of David and Tomoko Fuse. It's great seeing two of my favorite folders together! I have loved Derudas's butterfly since the first time I folded it. I was turned on to this butterfly by my friend Deiby in Brasil. (He is really into folding insects!)