THE TEMPERATURE OF THE BEE COLONY. 17 



In watching this colony it was found that the density, and conse- 

 quently the shape of the cluster, varied from day to day. When the air 

 outdoors was warm, the cluster expanded; with cold, it contracted. 

 The expansion usually did not cause the bees to cover more frames, 

 but caused them to cover more completely those frames which they 

 were occupying. Thus the expansion was usually downward toward 

 the bottoms of the frames and in the direction of the entrance. 

 With cold, the bees receded from the bottoms of the frames and from 

 the top bars. 



At all times the colony was sensitive to the slightest jar. The bees 

 were also especially sensitive to the light which burst in upon them 

 whenever the covering of the glass top was removed. If the hand 

 were passed over the glass, bees would fly toward it as if to sting. 

 This was noticed no matter how cold the day and shows that the 

 colony, and particularly the outside of the cluster, is far from torpid, 

 inactive, or semiquiescent. At practically all times there were bees 

 moving on the outside of the cluster or on the top bars of the frames. 

 Whenever the hive warmed up in the sun, although there were no 

 bees flying, this was evident. There can be no question, therefore, 

 of the alertness and activity of a colony in winter. 



One of the most surprising observations was the apparent inter- 

 change of bees from the inside of the cluster with those on the outside 

 of the cluster. As the writer watched the cluster, the head of a bee 

 would gradually appear from below the bees forming the shell of the 

 cluster. Finally this bee emerged and took her place with the others 

 on the outside. Similarly, bees were frequently seen to disappear 

 into the mass. The behavior was in no way general, but apparently 

 was going on constantly and gradually. The phenomenon was 

 repeatedly observed under all maimer of conditions and at different 

 times of day and night. By carefully arranging the covers, so that it 

 was unnecessary to remove them, and thus cause a jar, it was proven 

 that this behavior is normal and not the result of a disturbance of 

 the bees. It must be concluded, therefore, that in this way the same 

 bees may not be exposed to the outside cold for a long period. So 

 long as they are able to keep up their own body temperature they 

 remain outside, but when chilled they pass into the interior. Thus 

 there must be a continual interchange of bees from the outside to the 

 inside. Were it possible of observation, there would doubtless be 

 found a relation of the interchange to the meteorological conditions. 

 In cold weather the interchange may be expected to be greater. 



In severe weather the bees were especially compact and their 

 arrangement definite and constant. They were arranged side by 

 side between the tops of the frames, with their heads downward. At 

 the lower part of the cluster they were also arranged head down but 

 with a little less regularity. It is difficult to see just what this means. 



