Phase IV, hmmm... basically, desert ants get smart and attack a remote scientific outpost, eventually taking it over and hypnotically enslaving the man and woman who survive the attack. Early-70's monster/horror flick, heavily influenced by the Psychedelic Age.
I don't remember the hypnotic part. I remember at the beginning the sheriff rescues some little girl in shock after her parents get whacked (no sign of the parents) and there's this entymologist and they end up going down into the ant tunnels to gass the buggers.
Sigh--sounds like some classic MST3K--I miss the good old days. . .