412 AiSTNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



and of pine needle miners, which are apparently increasing in parts 

 of Oregon. 



INSECTS AFFECTING FOREST PRODUCTS. 



Studies have been made and practical experiments carried on 

 in connection with insect damage to crude forest products as well 

 as finished forest products. Variations in management and ex- 

 periments in sun curing, water submerging, seasonal cutting, and 

 chemical sprays have been carried on with very satisfactory results 

 in nearly all cases. Studies of chemical root preservatives, of woods 

 resistant to the attack of white ants, and of the effect of different 

 temperatures in kiln drying for killing the powder-post beetles 

 have also given interesting results. Much technical research work 

 with the insects concerned has been done. 



INSECTS AFFECTING SHADE TREES AND HARDY SHRUBS. 



The demand for information concerning insects of this class is 

 rapidly increasing. Many hundreds of letters of inquiry are re- 

 ceived from all parts of the country. Special studies are being 

 made of a number of species of insects that attack trees of this 

 class, special work being done in the East (at Washington) and in 

 the far West (at Palo Alto, Calif.), and the bureau is now in a 

 position to give advice in this direction which will be of great use 

 to the parking authorities of cities and towns. 



BEE-CULTURE INVESTIGATIONS. 



The work of the bee-culture laboratory, under the supervision of 

 Dr. E. F. Phillips, has been continued along the same general lines 

 as formerly. The laboratory and the apiary of the bureau are located 

 at Somerset, Md., near Washington. 



Behavior of bees. — The work on the responses of bees to changes 

 in the temperature and humidity conditions of the bee colony was 

 continued through the entire active season of 1922 and the same work 

 was carried on during the month of May, 1923, in order to increase 

 the data for the period of the heaviest honey flow. It is found that 

 there is a definite and A'^ery close control of the temperature of that 

 part of the hive in which brood is reared, but that in the parts 

 of the hive in which nectar is being stored and ripened into honey 

 the bees exercise little if any temperature control. This at once sug- 

 gests the desirability of insulation for the part of the hive devoted 

 to honey storage, but further experiments will be necessary to deter- 

 mine whether this would add materially to the honey crop. Exten- 

 sive records have now been collected and work has been begun 

 in their analysis and in preparation of some of the data for publica- 

 tion. It is found that each honey flow exhibits characteristic changes 

 in the weights hour by hour, doubtless because of variations in the 

 time of day when nectar secretion occurs in the different species of 

 plants. 



The investigation of the amount of brood within certain colonies 

 at weekly intervals throughout the brood-rearing season, conducted 

 by W. J. Nolan, is being continued with a few colonies during the 

 present season. During the summer of 1920 records were made on 



