﻿6 BULLETIN 14, # TJ. S. DEPARTMENT OF AGRICULTURE. 



in the hope that they may be of some interest to others they are here 

 reported in some detail. 



A large galvanized iron pan, measuring 5 by 3 feet, with sides 4 

 inches high, was made. In this stood a container on legs 8 inches 

 high. This container measured 4 by 2 by 2 feet. The sides and bot- 

 tom were of heavy wire, |-inch mesh, supported by a light wooden 

 framework. Twelve cubic feet of manure well infested with eggs and 

 larva? were placed in this container and sprinkled with water. Water 

 was also poured into the pan below to the depth of about 1 inch. 

 Surrounding and covering both pan and container was a fly-tight 

 inclosure made of a large cage, 6 by 6 by 6 feet. This prevented 

 further infestation of the manure, and an arrangement of traps at 

 the top of the cage made it possible to capture and keep a record of 

 any flies that might emerge. At the time for the emergence of flies 

 the sides of the cage were darkened with black cloth in order to 

 drive the flies into the traps at the top. Each day the larvse were 

 collected from the pan and counted, and each day the manure in 

 the container was sprinkled thoroughly with water and the pan was 

 washed out and again partly filled with water to drown the larvae 

 which fell into it. The records of Experiment No. 1 are summed up 

 briefly in Table I. 



Table I. — Migratory habit of housefly larvse; Experiment No. 1. 



Date. 



Larvse 

 collected 

 from pan. 



Flies from 

 traps. 



Date. 



Larvse 

 collected 

 from pan. 



Flies from 

 traps. 



1913 



Aug. 27 



28 



29 



30 



31 



Sept. 1 



2 



3 



4 



5 



337 



715 



1,550 



1 10, 000 



18,000 



2,160 



670 



263 



( 2 ) 

 304 





1913 

 Sept. 6 

 7 

 8 

 9 

 10 

 12 

 15 







88 

 102 

 23 

 19 

 9 

 5 

 6 





















3 



18 



8 



22 







23,999 



303 



1 Approximate. 



s Collected on following day. 



A few flies at the time of emergence fell into the water of the pan 

 and were drowned. Allowing for these and for the few which may 

 have escaped from the cage during the opening and shutting of the 

 door, the total number of flies may be placed at 350. It will be seen 

 from these figures that out of a possible total of 24,350 24,000, or a 

 little more than 98 per cent, were destroyed through the catching of 

 the larvae in the manner described. 



A second experiment was started on September 16. The manure 

 used was from the same source as in the first experiment and con- 

 tained practically the same proportion of straw. The same amount 

 was used, viz, 12 cubic feet. The only respect in which this experi- 



