THE FLIGHT ACTIVITIES OF THE HONEYBEE 



31 



the resumption of optimum conditions for flight. The third factor 

 seems the most probable. 



July 10 is a good example of a day of great dearth with long 

 flights (fig. 12). The average duration of the voyages in the period 

 from 10.45 a. m. to 3.30 p. m. on this day was 1 hour and 43 minutes. 

 During a portion of this period (from 12.36 to 1.15 p. m.) all the 

 bees (about 1,400) which set out from the hive were absent for as 

 long an interval as 1 hour and 54 minutes. The curve shows a 

 gradual lengthening of the duration of the trips from 15 to 36 



/U^yp- 



Fig. 13. — Graph representing flight data for May 9, 1922, a day of good 

 flow of locust honey 



minutes between 7 and 8.45 a. m., followed by rather sudden 

 lengthening of the trips from 36 minutes to 106 minutes between 

 8.45 and 10.45 a. m., which is the beginning of the period of ap- 

 proximate flight equilibrium mentioned above. At the end of the 

 day, as the flight activity comes to a close, a gradual shortening of 

 the duration of the trips is noted. A comparison of the evening 

 shortening with the morning lengthening m the duration of the 

 voyages shows that the lengthening in the morning is somewhat 

 sudden, whereas the shortening in the evening is more gradual. 

 These characteristics were noted on all the days studied. The 



