(Apologies to the OP about the thread hijack.)
Just take along an ounce or two of full-concentration deet. Using it sparingly, even if the bugs are bad, it works.
Where can I get full-concentrate deet?
Frank,
REI has it. I have an older tube, like the "Coleman Pen Spray" in the REI page, but it contains nearly 100% DEET. I like the high concentration because it is less total weight.
To use it sparingly, I just spray one pulse on my hand, then rub the hand where I need the protection.
DEET is really strong stuff. It dissolves paint and labels from cameras, and makes hiking pole handles sticky. So wash the hands after using it!