Smith helmets with Koroyd and
Trek/Bontrager WaveCel helmets will keep out most bugs while allowing normal ventilation. Several friends wear those and are happy with them.
In years of riding I've trapped a bug in my helmet only once, a week ago -- a June bug. No big deal but could have been unpleasant if it had been a wasp or bee. Fortunately a friend who rides the same routes I do seems to be the bee and wasp magnet so he clears the road for me.