REPRESSION. 151 



plats where small applications were made. On account of the 

 apparent contradictions and the variations due to the seasons it is 

 considered necessary to continue the work another season before 

 definite conclusions as to the practical value of arsenate of lead can 

 be drawn. 



MACHINES. 

 FIELD MACHINERY. 



Many attempts have been made to perfect machines that will 

 assist in the warfare against the weevil. The only one of direct 

 value that has been perfected is the chain cultivator (PI. XX, h; 

 PI. XXI) invented by Dr. W. E. Hinds, formerly of the Bureau of 

 Entomology, and patented by the Department of Agriculture for the 

 benefit of the people of the United States. Its construction is based 

 upon the discovery that the weevils in the infested squares that fall 

 in such position as to be reached by the sun soon die. In a cotton 

 field many of the infested squares fall within the shade of the plants, 

 and are thus protected. The chain cultivator is designed to drag 

 the fallen squares to the middles of the rows and leave them exposed 

 to the sun. This it has been found to accomplish in a satisfactory 

 manner. In fact, in tests the use of the machine has been found 

 to result in a decided gain in production. 



Although the chain cultivator was designed primarily for bringing 

 the squares to the middles, it was found in field practice to have a 

 most important cultural effect. The chains (so-called "log chains") 

 are heavy enough to establish a perfect dust mulch and to destroy 

 small weeds that may be starting. In fact, it is believed that this 

 cultural effect would more than justify the use of the machine, 

 regardless of the weevil. In view of the effect against the insect and 

 the important cultural effect, it is believed that this implement or one 

 similar to it should be used by every farmer in the weevil territory. 



The chain cultivator is now regularly manufactured by one of the 

 large dealers in farm implements, but a satisfactory machine can be 

 made by any blacksmith. Full directions are to be found in Farmers' 

 Bulletin 344, a copy of which may be obtained upon application 

 to the Secretary of Agriculture. 



Some forms of cultivators now in use allow the attachment of 

 boards which drag on the ground and carry the infested squares to the 

 middles. In fact, the principle of the chain cultivator can be incorpo- 

 rated in many implements now in use. It is strongly recommended 

 that this be done for weevil control as well as for obtaining a dust 

 mulch. 



1 Many machines have been designed to jar the weevils and 

 infested squares from the plant and to collect them, to pick the fallen 

 squares from the ground, to kill by fumigation, and to burn all 

 infested material on the ground. The Bureau of Entomology has 

 carefully investigated the merits of representatives of all of these 

 classes, beginning in 1895 with a square-collecting machine that had 

 attracted considerable local attention in Bee County, Tex. Up to 

 the present time none of these devices has been found to be practical 

 or to offer any definite hope of being eventually successful. At one 



1 The following three paragraphs are modified from Bull. 51, Bureau of Entomology, p. 157. 



