The LENGTH of the inner tube where the bees are trapped is LONGER.
and the air flow area is larger.
When you take a given volume of air flow and you spread it out you have a gentle breeze.
Take that same given volume of air flow and restrict it to a 1" opening and you have suction a lot of it!
the bees are sucked through the tube and when they are OUT of the tube they are immediatley in a light breeze, they don't wt much so their momentum is not that great and they can easily overcome the force of being thrown.
The extra lenght, 24" is enough for the bees to slow down, try to regain some "flight" before landing on the bottom of the vac.
Most bees after inside of the vac will cling to the side of the inner tube where the screen is NOT.
Controlling your suction speed it also important. I use just enough to get them off of what ever they are hanging on to.