"Instinct and intelligence" in ants

Skeptical of some of the statements made by Hingston concerning the intelligence of ants in his Instinct and Intelligence , the author carried out some experiments to test the verifiability of the behavior in question. The experiments concerned (1) whether ants have a method of signalling their fellows when they discover food that they cannot drag to the nest alone, (2) whether ants leave an olfactory clue along the pathway, (3) whether the number of ants eating at a piece of food is proportional to its size, and (4) whether ants have memory for a specific stimulus such that they can react appropriately to it after a period of from 12 to 24 hours. In every case except one the author failed to verify Hingston's observation. In this one case (3) his interpretation differs markedly from that of Hingston.