What is this wonderful substance called royal jelly? Royal jelly is a glandular secretion produced by the nurse bees to feed the larvae. Pharyngeal glands of bees produce this substance in the same way the mammary glands produce milk. The fact is of great biological interest. No other insects in the world are known to have evolved such a process. Royal jelly is fed to all bee larvae for the first three days after hatching from the egg. Beyond that point for all those destined to become drones this food is diluded with honey and pollen. The larvae which are destined to become queens are fed throughout the whole of the larval period on pure royal jelly. Royal jelly must be a substance of tremendous nourishing power. On this diet alone, the honey bee larva increases in weight 1500 times in five days. This is as if a seven and a half pound baby should increase in that time to five tons.