I just recieved Squadron/signal's book P-35, Mini In Action. It's a good book but I noticed the line drawings show radio antennas running from the tip of the rudder to each wingtip and the fuselage. This is OK, but none of the photos show any antenna at all.

The pictures are not of the highest quality but I'd think the wires should show up some. What gives?

You can see lots of wires here:
http://www.wpafb.af.mil/museum/early_years/ey14.htm

There was a discussion a while ago about this antenna arrangement on the P-40, the wires attach just inboard of the wing tip. I have seen this document elsewhere as an IFF system ?

EDIT: The wire from the tail to the canopy is "standard comm"

If this is it - check the antenna from the cannopy to the tail. There is a wire from the tip of the wing to the tail also.
Its a small wire so it's hard to see.
http://www.wpafb.af.mil/museum/research/p35-1.jpg

edit

here is another better picture
http://www.wpafb.af.mil/museum/early_years/ey14.htm