Again. Killing the adult bees would kill the larvae.
Edit:
A more detailed explanation:

As you can see the stages of the Development of bees can be divided into Three main phases: egg, larvae and pupae.
In the larval stage the larva Depends on being fed by spesialized bees (nurse bees or nursing bees). If all adult bees are killed and you only have eggs or larvae, the hive is doomed.
In order for the hive to survive long term it needs a Queen. She is the only individual laying eggs that gives rise to worker bees(females) and New Queens.
New Queens form if a larvae is given a special kind of Food during day 1-3 in the larval stage, royal jelly. If no larvae are fed royal jelly, no New Queens forms and if the old Queen is dead, the hive is doomed.
In order to make more beehives, the simplest Method is to separate the queen from the nurse bees + comb (wax) with eggs and/or larvae. The worker bees will sense the abscence of a queen and will start feeding royal jelly to selected larvae.
This was the short explanation.