I’ve made several traps in the past with varying degrees of success. Here’s one specifically designed that allows the yellow jackets to enter but not the honey bees. I think it is a 5/32 size hole. Last year I tinkered with the mix formula. Instead of totally sweet which would attract the honey bees I stumbled onto a mix of apple sauce, vinegar, and a spoonful of sugar (just enough to get a fermentation going). The yellow jackets like the CO2 I think and the vinegar is not attractive to the honey bees. I used a 2 liter bottle and filled it about half way full in a short time. If you get your bait mix down it will not attract the bees at all and you can then open up the entrances for the yellow jackets. See More