Fecha de publicación: 28/04/1981 Fuente: WIPO "hive" An observation hive including a main frame containing a standard frame and a shallow frame and having a hinged cover closing the top thereof, the main frame having dovetail grooves on the inside thereof extending from the upper end and terminating at support surfaces spaced from the bottom, the standard frame having support extensions on the upper edge thereof extending into the dovetail grooves and resting upon the support surfaces, spacer blocks shaped complementary in cross section to the dovetail grooves and disposed therein and resting upon the support surfaces and supporting extensions on the shallow frame that extend into the dovetail grooves and overlie the spacer blocks, and spacers on the under side of the cover which when the cover is closed press against the top of the shallow frame.