Here are a few more pictures with dimensions for building the upper entrances previously blogged here. Based on the George Imirie idea that an upper entrance would increase honey production, this is a slight improvement in design with a reduction of spacing between boxes to 3/8″. The bees take to them readily after a short period of discovery. Other benefits may include increased ventilation, less brood box congestion, less travel stain, and increased hive efficiency at removing nectar moisture. Enjoy!