2 BULLETIN 245, U. S. DEPARTMENT OF AGRICULTURE. 



favorable place for the deposition of eggs. A treatment two or three 

 times a week ought to suffice for all these cases except where large 

 quantities of organic material are added, when the borax application 

 should be made immediately, using the same quantity as in the treat- 

 ment of horse manure. The best results are always obtained when 

 the borax is applied in solution daily, as it is effective against the 

 eggs and the maggots during their feeding period. (Table V, series 52, 

 G and H.) Borax probably has no effect on the pupae or adult flies. 



GENERAL PLAN OF EXPERIMENTAL WORK. 



CAGE EXPERIMENTS. 



The plan of the work was the same as that outlined in Bulletin No. 

 118, and in addition a few experiments were carried out in concrete 

 pits. New cages were constructed for the experiments at Arlington. 

 In order to prevent the escape of larvae by migration, the galvanized- 

 iron pans in the cages in which the manure was placed were made 

 2 feet deep, and the small openings in the bottom of the pans through 

 which the water drained off were covered with fine wire gauze. The 

 legs were made 8 inches high to facilitate the removal of any larvae 

 which might get into the drip pans. 



The manure was sprinkled in three layers by putting 2 bushels of 

 manure in the cage and applying 2\ gallons of the solution. This 

 was repeated in the second layer of 2 bushels. Finally the remaining 

 4 bushels were added and the last 5 gallons of the solution applied. 

 When a chemical was applied in dry condition it was scattered over 

 the surface of the manure, which was also treated in three layers, and 

 10 gallons of water were afterwards added. The manure hi the con- 

 trol cages - was sprinkled with water equal to the volume of the solu- 

 tions used. The flies which were caught in the traps attached to the 

 top of the cages were chloroformed and counted, and at the end of 

 each experiment a comparison of the total number was made, and 

 from these counts an index of the effectiveness of the chemical was 

 obtained. Only fresh manure was used in the experiments, and every 

 effort was made to provide for an even distribution of fly eggs and 

 larvae. That it was impossible to secure an equal infestation in all 

 cages is evident from a comparison of the fly counts from the con- 

 trol cages. 



OPEN-PILE EXPERIMENTS. 



A few open-pile experiments were carried out at Arlington on the 

 same plan as during the previous year. The most important open- 

 pile experiments were conducted at New Orleans during November 

 and December, 1914. In most of the New Orleans open-pile experi- 

 ments 4 bushels of manure were sprinkled with 5 gallons of solution 

 daily, and this was repeated four times, making a total pile of 16 

 bushels treated with 20 gallons of solution. The total number of 



