Sometimes it may be necessary to exterminate honey bees that are in the walls of a house because of the difficulty of removing them. Some exterminators will not kill bees because they say they are an endangered species. Actually, bees are not really endangered because it is possible for beekeepers to control the pests and diseases and to replace hives that die in the winter (although it may be expensive).
It is difficult to find a beekeeper to remove them. An exterminator would probably squirt some dust in the hole to kill the bees (such as Apicide or Seven). Dust works well because it gets tracked into the nest, but others may use wasp spray.
If you could remove some boards to access the combs, it is possible a beekeeper could remove the bees and put them in a hive. This process is difficult because it may damage your home. The brood comb must be cut out and wired into frames that get put in a hive. If the queen is transferred to the hive with brood, the rest of the bees will eventually follow, although it may be necessary to leave the hive there for a few hours or overnight.
If you were to kill those bees with some dust without removing the comb, it may be better to wait until spring. They might die on their own during the winter and there will be much less honey in the nest in the spring. The problem with the honey is that after you kill the bees the waxmoths often destroy the wax honey comb and the honey could drip between your walls and possibly cause damage.
– Greg Hunt, Purdue University