18 



BULLETIN 780, U. S. DEPARTMENT OF AGBICXJLTUEE. 



The percentage of infected bees found during the spring and sum- 

 mer remained quite constant, increasing imexpectedly in September. 

 The reason for the increase can not be assigned at present. 



Out of the 25 colonies in the apiary in March, 1913, 1 (No. 12) died. 

 As this colony contained a high percentage of Nosema-inf ected bees, 

 and as it dwindled until it disappeared, it may be assumed that 

 Nosema-disease was the immediate cause of its death. As in the 

 preceding year all of the colonies that lived behaved much as do 

 uninfected ones. 



In this year another experiment was begun in the apiary. This 

 one is described as experiment No. 2 (p. 25). 



Studies similar to these made, in 1912 and 1913 were continued 

 throughout 1914 and until June, 1915. While in the main the col- 

 onies of the apiary were those of the previous years, naturally there 

 had been some changes. The results obtained are summarized in 

 Table IV. 



Table IV. — Results obtained from May, 1914, to June, 1915, from a study of Nosemia 



infection in an apiary. 



HxplamtimofTaUetV.-'rhe oplonira reported in Table IV for 1914 do not bear the same numbers that 

 rere assigned to them for 1913 m Table III except those designated by numbers in oiiotaHnn^Svf Jrh. 

 arst 9 colonies reported in the table for 1915 bear the same nSiibers tW^d to Sl4 The?d™^rtvof »l! 

 omes numbered 6y letters "t". to "i," inclusive, had been lost through change made in the a™iSry. 



