Amr bin Shu'ayb relates from his father, from his grandfather, that Hilal, one of the Banu Mut'an, came to the Messenger of Allah (peace and blessings be upon him) with the tithe of his honey bees, and asked him to reserve a valley called Salabah for him, so the Messenger of Allah (peace and blessings be upon him) reserved that valley for him. When Umar bin al-Khattab (may Allah be pleased with him) became caliph, Sufyan bin Wahb (may Allah be pleased with him) wrote to Umar (may Allah be pleased with him) asking him about that. Umar (may Allah be pleased with him) wrote to him: "If he pays you what he used to pay to the Messenger of Allah (peace and blessings be upon him) as the tithe of his bees, then reserve Salabah for him; otherwise they are merely rain-flies (wild bees), which anyone who wishes may eat (from)."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7460