Fecha de publicación: 08/04/1986 Fuente: WIPO "beekeeper" Abstract of the Disclosure To promote the collection and harvesting of propolis from a bee colony a fine mesh screen through which bees are unable to pass is located in a central ventilation passage of the colony by registering it with the scraper screen of an internal pollen trap. The bees deposit propolis on the screen which can be removed without dismantling the hive.