A system for delivery of a substance into a hive box of a beehive is provided. The hive box includes a wall and a plurality of comb support members mounted on the wall and the beehive has a bee space located adjacent to the comb support members, oriented in a plane substantially perpendicular to the wall. The system comprises at least one aperture aligned with the bee space and apparatus for insertion into and removal from the aperture. At least part of the apparatus is shaped to be received and held in the aperture. Apparatus for delivery of fluid into a hive box of a beehive is also provided, the hive box including a wall and a plurality of comb support members mounted on the wall, the apparatus comprising at least one opening aligned with the bee space, wherein the opening is smaller than a bee space in at least one direction.