Some of the wording will need clarified. The last sentence should read something along the lines of, The copy comes into play with damage equal to the amount of damage on Swarm of Wasps. Otherwise a 4 health swarm splits and you end up with a 2 health swarm and an 8 health swarm.
I'm not sure if I like the balancing of the card after that, either. 4 dice zone attacks that only hit unarmored targets will still kill off level 1 beast master cards in droves along with most imps, huginn, sosruko, fellela, thoughtspores, invisible stalker, and most skeletons. Bee stings will still hurt oozes, zombies, and earth elementals, which seems thematically strange.
It is also worth noting the attack will hit the bees since it is a zone attack, but with self replication built in, i'm not sure that's a strong enough penalty. One could put regen on a swarm and have it divide into mobile hails of stones indefinitely.
Maybe try lowering the number of dice rolled in favor of piercing. I know piercing wasps don't make sense, but the mechanic of bees flying into joints in armor, eyes of monsters, etc helps with the swarm feel and balances the card against unarmored targets a fair bit.