Abstract Mortalities in 68 populations, of about 100 bees each, confined to small cages containing a piece of comb were tabulated daily and symptoms of the disease were observed until all bees had died. Various experimental treatments were administered, the most important of which was the presence or absence of a queen in each population. Queenless populations usually showed some bees chewing and nibbling upon others (a symptom of the disease) in 3–5 days, whereas queenright units usually did not show this symptom for 10 days or longer. Average length of life in queenless units was about three-fourths as long as in queenright units. Some confirmation of these results was obtained from larger populations allowed to fly in a flight cage.