230 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



laboratory at Mecca, Cal., closed. The life history of the date-palm 

 scale has been worked out satisfactorily and its natural enemies 

 well studied. Sufficient data have also been secured on the life 

 history of the Phoenicococcus scale to aid materially in controlling 

 this pest. 



Mediterranean fruit fly. — As indicated in the last annual 

 report, the control and inspection of fruits shipped from the Hawaiian 

 Islands to the mainland of the United States are conducted in coop- 

 eration with the Federal Horticultural Board. Life-history studies 

 of the Mediterranean fruit fly from the standpomt of parasite intro- 

 duction were conducted and the susceptibility of citrous fruits to 

 fruit-fly attack was investigated. The life history of the melon 

 fruit fly was thoroughly studied and a bulletin on this subject was 

 issued. As in the past, intimate cooperation was maintained with 

 the Territorial Board of Agriculture of the Hawaiian Islands in the 

 introduction and estabhshment of parasitic enemies, 



WORK IN BEE CULTURE. 



The work in bee culture, which remains in charge of Dr. E. F. 

 Phillips, was greatly facilitated by the establishment of a field 

 laboratory with the apiary at Drummond, Md., a suburb of Wash- 

 ington. 



Wintering of bees. — ^Again the principal work was the contin- 

 uation of the investigation of bees in winter. The work was confined 

 chiefly to bees wintered out of doors. Various methods of packing 

 colonies wore employed for the conservation of the heat generated 

 by the boos, and, while certain differences were observable, it was 

 found that in general the more completely bees are packed, the more 

 nearly ideal conditions are approached. The choice of insulating 

 material is of minor importance, since by using plenty of shavings, 

 sawdust, or leaves the beekeeper can give the desired protection. 



For the first time the wmd velocities directly over the hives were 

 recorded, and it was found that when a well-insulated colony is 

 subjected to a wind of about 20 miles per hour, the beneficial effects 

 of the insulation are virtually nullified. At the same time a careful 

 record was kept of outside temperature, humidity, rainfall, and 

 cloudiness. The effects of changes in temperature have been described 

 in previous reports, and the investigation of the effects of other 

 meteorological factors will be continued. 



Several colonies were wintered in a specially protected room in the 

 laboratory cellar, where the temperature was kept much higher than 

 is usually considered desirable. The results obtained justify the 

 conclusion that a cellar in which bees are wintered should have a 

 temperature of at least 50° F. In conjunction \\ath this work one 

 colony was weighed hourly on specially constructed scales with the 

 minimum disturbance, and it was found that when the temperature 

 of the cellar was lowered the consumption of food was increased, 

 which, of course, resulted in an increase in the feces accumulated, 

 with their corresponding harmful results. 



A study of the commercial hives in which insulation is retained 

 throughout the year was undertaken, the object being to acquaint 



