It was the compound secreted by the pharyngeal glands of worker bees, fed to all bee larvae.

In the pharynx, the pharyngeal glands secrete mucus.

The pharyngeal nerve innervates pharyngeal glands.

Greater petrosal nerve - provides parasympathetic innervation to several glands, including the nasal gland, palatine gland, lacrimal gland, and pharyngeal gland.

Cilia pull the food through the mouth in a stream of mucus and through the oesophagus, where it is partially digested by enzymes from a pair of large pharyngeal glands.