EARLY WORK IN THE BEE-CITY 93 
keep up the gentle circulation which then is alone 
needed. 
Sometimes, when the colony is unusually large, 
the fanning-party will be divided into two detach- 
ments, one at each side of the entrance, leaving 
the centre for the inflow of air. In this case a 
double-loop system of ventilation appears to be 
formed. 
