Before Bear Grills and Ray Mears there was Lofty Wiseman. This is from Lofty's "SAS Survival Handbook."
"WORMS: Contain the highest class of protein with a large proportion of essential amino acids and are easily collected. Starve them for a day before you eat them or squeeze them between the fingers to clear muck out of them. Worms can be sun- or force-dried, one easy method is to leave them to dry on a hot stone, and then ground into a powder to add to other food as required."