Just heard this at the bee meeting.
Put a mixture of sugar and borax in a straw by the hive. The sugar coats the borax, which they take back to their nest and it kills the ants.
I've always done borax:sugar:water in 1:1:1 ratio. It's quite effective on ants. If you want to make sure the bees can't get it, then put it in a tupperware sandwhich box with 1/8" holes in it.
The ants I have are several yards away from my hives. I kick the tops off the ant mounds and pour a little Borax on it. It usually takes care of that mound.
Joe D