SummaryThe maximum sizes of 83 colonies varied greatly, the biggest colony being five times the size of the smallest. Many of the colonies that failed to grow big stopped growing quite early in the summer without losing their laying queens. This suggests that selective breeding might be more profitably directed towards uniformity than towards increase in colony size.Twenty-three colonies kept with more hive space than they could occupy had an average of about 1100 bees per British comb (1400 per Langstroth comb) on the combs they were occupying. From this, and several published estimates of colony sizes, it was deduced that an average colony needs about 3½British 11-comb boxes or 3 Langstroth 10-comb boxes to accommodate its adult bees.