10 BULLETIN 93, U. S. DEPARTMENT OF AGRICULTURE. 



March 15. During this period the cluster temperature followed the 

 room temperature, but remained constantly over 20° warmer. The 

 room was again cooled slowly, and the cluster temperature dropped 

 until on March 16, at 3 p. m., the room was 49° F. and the cluster 

 77.5° F. As the room continued to cool, the cluster temperature in- 

 creased, the bees responding to the colder temperature, until at 4.15 

 a. m., March 17, the room was 48° F. and the cluster 88° F. The 

 room then gradually warmed, and again the temperature of the 

 cluster dropped and then again rose with the room temperature, 

 remaining always over 20° warmer. At 6.45 p. m., March 19, the 

 brine was turned on full and the room cooled rapidly, reaching the 

 minimum of 13° F. at 9 p. m., March 20. At no time, however,, 

 did any of the thermometers in the hive record a temperature below 

 33° F. Here it remained constant within 0.1° F. for about six 

 hours, during which time the cluster temperature varied between 

 86.5° and 89.5° F. (a difference between the room and the cluster 

 temperatures of 73° to 76° F.). The brine was now shut off and 

 the room again warmed until 9 a. m., March 24, when it reached a 

 temperature of 44.5° F. During this warming the cluster cooled 

 until at the close it was varying between 72° and 79° F. 



As stated above, the colony was now (9 a. m., March 24) removed 

 for a flight and put back the same day at 7 p. m. In the meantime 

 the room was cooled to 33° F. When the bees were put back into the 

 room the temperature of the entire inside of the hive showed great 

 variation and naturally an increase due to the warming up while out 

 of doors and to the activities of a good flight. The points outside 

 the cluster dropped rapidly, but it was midnight, March 25 (31 

 hours), before the curves of temperature again appeared normal. 

 The room was slowly warmed to 63.2° F. at 6.30 p. m., March 26, 

 and then slightly cooled to 54° F. at 6 a. m., March 27, and again 

 warmed to 58.5° F. at the close of the series, 4 p. m., March 28. 

 After the flight the temperature of the cluster never dropped below 

 89.5° F., and the highest temperature reached was over 95° F. (soon 

 after the flight). Thermometer 6 remained high, but thermometer 

 2, which had previously been high, now approached the other ther- 

 mometers, probably due to a rapid loss of bees and to a decrease in 

 the number of bees during the flight. It must be recalled that these 

 bees had been confined for an abnormally long time and were sub- 

 jected to treatment which is at least unusual. After this colony was 

 taken from the room for the last time it was found that thermometer 

 6 was over a patch of larvae, and, estimating as accurately as possible, 

 the eggs from which these hatched must have been laid at the time 

 when the room was coldest (March 20-21) and when the cluster tem- 

 perature was at its highest point. There had been no brood previ- 

 ously, according to the temperature records as compared with those 



