BUREAU OF ENTOMOLOGY. 325 



done were revised at the beginning of the fiscal year and the work 

 is here reported under the new projects. 



Behavior or bees. — Work has been begun on a study of the tem- 

 perature and humidity conditions in all parts of the hive during 

 the active season. During the latter part of the active season of 

 1921, temperature and humidity records were made hourly during 

 the day, with occasional periods when records were made at night 

 and day for several days at a time. Careful records are made of 

 the plants that are furnishing nectar and pollen and of the hourly 

 weights of the hive under observation. This work continued with- 

 out interruption until early June, 1922, at which time certain diffi- 

 culties were encountered with the thermocouples and it was neces- 

 sary to discontinue the work for a short time in order to rewire 

 the hive. The work will be continued throughout the active season 

 of 1922. It is too early at this time to summarize the results of 

 this work, but there can be little doubt that it will result in a better 

 understanding of the temperature and humidity conditions pre- 

 vailing in the hive during the summer. This in turn may, as in 

 the case of the wintering work, lead to important modifications of 

 the hive or of its management, and in any event will help to make 

 clear the reasons for some of the phenomena which beekeepers have 

 long observed but have not understood. 



The work on the rate of increase and decrease in brood rearing 

 is being continued. 



In June, 1922, a study was begun on the responses of bees to 

 lights of various colors and intensities. It has long been known 

 that bees respond to numerous light stimuli, but so far no detailed 

 study has been made on this subject, aside from some work on 

 the responses of bees when their sight was impeded. Numerous 

 experiments have been made on the preference of bees for certain 

 colors, which have shown conclusively that they recognize color 

 differences. It is hoped that the present work will clear up some 

 of the uncertainties in this field. 



At the opening of the active season of 1922, a study was under- 

 taken of the flight of bees to and from the hive, as modified by 

 temperature, light, the secretion of nectar, and various other ex- 

 ternal factors. This work is being done by A. E. Lundie, of 

 South Africa, who is spending some time in the United States in 

 a study of beekeeping. He has devised an ingenious apparatus 

 by which the movements to and from the hive may be accurately 

 counted automatically, and this has been installed for several 

 months. Records of outgoing and incoming bees, of the weight 

 of the hive, and of the temperature and other external conditions 

 are made every quarter hour from daylight until dark daily. It 

 is hoped that the results of this work will throw some light on cer- 

 tain details of bee activity so far not clearly understood. 



The ability of queen bees and drones to feed themselves, without 

 the intervention of worker bees, was established in some recent 

 feeding experiments. 'While under hive conditions both the queen 

 and drones are usually fed by the workers, they are both capable 

 of taking food independently of the workers. 



Physiology of bees. — In connection with the study of the winter- 

 ing problem several years ago some feeding experiments were under- 

 taken to determine what carbohvdrates are available to bees as food. 



