It is practice in modern-day beekeeping to have part of your hive separated by a gap that is large enough for the worker bees to get through but too small for the queen (a queen excluder). This ensures that the queen only lays eggs in part of the hive (the brood box), and you can freely harvest the rest for honey. This was invented by the Rev. Lorenzo Langstroth, in 1852.
A bee-keeper will certainly write up the importance of ensuring that the eggs and honey are not intermingled in practical notes on bee-keeping. All the more so in that old-fashioned bee-keeping practices were slow to change.
Its literary effect is to underscore the sincerity of his retirement: writing up how to keep bees, instead of catch criminals as he did in the years when he worked, show how his interest have changed. The segregation of the queen bee is probably to add some local detail that he really does know his stuff.