18 



BULLETIN 1328, U. S. DEPARTMENT OF AGRICULTURE 



of their bodies that they have been caught in the storm and after 

 drying have flown back to the hive. 



Showers, if they are of sufficient strength, produce the same effect 

 as a severe storm, the periodicity of the curve corresponding exactly 

 with the time of each shower. The effect of a shower of rain last- 

 ing only from 5 to 10 minutes is well illustrated by the records for 

 May 19 (fig. 6), where a marked depression in the two curves is 

 produced, the record of the weight of the hive showing a sudden 

 increase during the shower, to be followed immediately by an equally 

 abrupt decrease on the resumption of clear weather. 



Cj; /400 





Fig. 6. — Flight, temperature, and hive-weight data for May 19, 1922, showing the 

 effect of a shower of short duration on flights 



The flight on an overcast day with some rain is illustrated by 

 that of May 18 (fig. 7). The day set in dull with the following 

 weather records: 



Weather conditions 

 At 6.30 a shower of short duration occurred. 



Time 



6.00 to 9.15 Heavily overcast. 



9.15 to 10.15 Sprinkling. 



10.15 to 11.00 Light rain. 



11.00 to 11.45 Sprinkling. 



11.45 to 12.15 Steady rain. 



12.15 to 1.00 Heavy rain. 



1.00 to 1.30 Light, steady rain. 



1.30 to 2.00 Sprinkling. 



2.00 to 2.15 It has stopped sprinkling. 



2.15 to 2.45 Brighter, though still overcast, light frequently varying in 

 intensity. 



2.45 to 3.00 Becoming darker again. 



3.00 to 3.15 Heavily overcast. 



