24 BULLETIN 96, U. S. DEPARTMENT OF AGRICULTURE. 



toms of the frames or even out at the entrance. Consequently that 

 space which was outside the frames assumes cluster conditions. 



Early in the season/ averaged 3° C. higher than o at all times; 

 at the end of the season, September, it averaged from 5° to 6° C. 

 higher. By the middle of May /stood only 1 ° or 2° C. lower than the 

 thermometers in the cluster, although the thermometer in the outside 

 air was much lower. Throughout the summer there was practically 

 no difference between c and /. During the storm period, as will 

 be seen in Table IX, which is discussed farther on, / ranged even 

 higher than the prevailing cluster temperature. This was undoubt- 

 ed\j due to the massing of the bees below the frames as they were 

 crowded in from the alighting board. 



THE EFFECTS OF STORM. 



Since the summer of 1908 was remarkably dry and free from storms, 

 it is not possible to draw any definite conclusions upon the effects 

 of storms, cold waves, and winds upon the cluster temperature. 

 The only severe storm of the summer occurred in the latter part of 

 August. The outside thermometer went as low as 14° C. (57.2° F.), 

 while before and after this period there were frequent readings 

 ranging from 20° to 30° C. (68° to 86° F.). During the storm there 

 were several high winds. These, however, did not blow directly in at 

 the entrance. The bees were thus confined for three days, and at 

 times showed much evidence of shifting and massing at different 

 parts of the hive. In a glass observatory hive the bees were actually 

 seen to cluster now in one part of the hive and then in another. 

 The wind and rain also drove the bees in off of the alighting board 

 and forced them to hang from the bottoms of the frames. If the 

 readings of the thermometers nearest the outside of the hive are 

 rightly interpreted, the cluster withdrew from the walls of the hive, 

 and this caused a decrease in the temperature at these points. While 

 there is some evidence in the figures that the cold outside the hive 

 had its effects on the center of the cluster, the temperature was not 

 permitted to remain below 34° C. (93.2° F.). No fall was recorded 

 lower than 33.8° C. (92.84° F.). Thus the bees appear to be able 

 to control and conserve the temperature with remarkable constancy, 

 even though there be high wind and relatively low temperature. 

 Table IX, in comparison with the figures for a bright day in Table 

 VIII, reveal these facts. 



