BEES IN COLONIES AFFECTED BY EUROPEAN FOULBKOOD 19 



the same sample from which infectious dried scales were used to in- 

 fect colony H. After this comb had remained in the laboratory, 

 wrapped in paper for about 3 weeks, it was placed in the strong 

 colony in the observation hive. The frame was first placed in the 

 middle of the hive for about an hour and was then removed to the 

 outside, where the work of the bees on it could be watched. A large 

 number of what appeared to be young nurse bees were already hard 

 at work on the dried diseased material. The bees, working on the 

 dried gummy masses, would wet the mass with their tongues for a 

 while and then tear at them with their mandibles, at times removing 

 pieces large enough to be seen from the outside. Often these small 

 pieces were apparently dropped to the bottom board. No one bee 

 worked long at one place. Those bees working particularly on the 

 fresh, moist material, when leaving, would carefully wipe their 

 tongues with their front feet, thereby transferring some of the in- 

 fection to them. Other bees were at work carrying away the larger, 

 more easily removable dead masses. The entrance also was watched 

 to see if any of this material was carried out. Several bees were 

 observed carrying out portions of dead larvae or pupae. One bee 

 carried a piece about 2 yards before dropping it. Others dropped 

 what they were carrying soon after leaving the entrance, but on ex- 

 amining the surface of the ground about the entrance, very little 

 material could be distinguished, so that apparently most of the ma- 

 terial removed must have been carried some little distance before being 

 dropped. After about an hour's work it was apparent that consider- 

 able progress had been made. This comb was removed before it was 

 entirely cleaned and later placed in another healthy colony for obser- 

 vation. It was quickly cleaned up and quite a bit of nectar placed 

 in it and, eventually, several square inches of brood. Observations, 

 however, had to be stopped before any appearance of recurrence was 

 noted. This same observation hive was given one or two other dis- 

 eased combs to clean, but with the repeated probable infection from 

 these sources the colony was so strong that no disease was noted in 

 it during the entire season of observations. 



POSSIBLE INFECTION THROUGH QUEEN 



Colony M was a small nucleus made to receive the old queen from 

 diseased colony K from McGraw, N. Y. The queen was introduced 

 on June 20, 1918. For a while she laid fairly well, it being neces- 

 sary to add one or two more combs. But later her brood became 

 more and more scattered. Finally, on July 8, there was observed one 

 dead larva, which looked suspicious, but which, on microscopic ex- 

 amination, proved to be negative. On July 10, however, one definite 

 cell appeared and several other slightly yellowish, abnormally colored 

 larvse. This dead larva contained BaciUus pluton. From then on 

 until this queen was killed and the colony united with another dis- 



