I have to agree with you regarding their nature. While bees are certainly useful, wasps would not be so much, and the Hebraic interpretation of the poisonous horn in FRONT would apply to neither.
I, too, have understood the verse to refer to beasts of burden and would guess these exotic two to be mammoths and mastodons, both of which are evidenced to have been concurrent with man on the American continents, both north and south. They would especially be useful to carry, pull, raise and build. As another here has said, the horns (tusks) would be dangerous if not trimmed ot blunted, especially.