Ill 



direction of the wind for several da3^s after April 15 was from the 

 south, and during this time few if any weevils came to the plots of 

 seppa which had been preserved. Upon April 22 and 23 the entire 

 field was thoroughly cultivated. At about the same time the wind 

 changed, blowing from the north. During the next two or three 

 days large numbers of extra weevils were found along the ends of the 

 rows on the northern edge of the plots under observation, at a dis- 

 tance averaging less than 50 feet from the ends of the rows. At that 

 time planted cotton had not broken ground and all other seppa cotton in 

 the field had been destroyed about 10 da^^s before these weevils were 

 found. Considering the change in direction of wind which had taken 

 place in the meantime, it is evident that the movement of the weevils 

 was in some degree related to the direction of movement of the pre- 

 vailing wind. 



Between May 3 and 28 about 60 healthy hibernated weevils were so 

 marked as to be individually recognizable. These weevils were placed 

 upon vigorous seppa plants, and 

 observations made to locate 

 them upon succeeding days. 

 To facilitate the keeping of the 

 records, the plot was divided by 

 east and west lines into 8 sec- 

 tions, with 45 rows running 

 north and south. At the begin- 

 ning of the observations with 

 each weevil a stake was placed 

 beside the seppa plant upon 

 which the weevil was located, 

 with a tag bearing data as to the 

 date, the number of the row and section in which the plant was located, 

 with the number of the weevil and its particular mark. Three-fourths 

 of the weevils thus liberated were located upon two or more dates. 

 When a weevil was found to have moved, the distance and general 

 direction of the movement were recorded upon the tag, which was 

 then moved to the new location. When a weevil was not found upon 

 a succeeding date, the original location of the tag was preserved until 

 the weevil was either found or given up as lost. If found after an 

 interval of several days, the range of time during which the total 

 movement from the original location had been effected was noted upon 

 the tags. Doubtless, in many cases, the movement recorded was a 

 component result of several movements, but, even if so, the general 

 result of the observations is not affected by that fact. 



In compiling the general results of these observations, all move- 

 ments in one direction are taken together. If it be assumed that these 

 movements radiated from a common center of infestation, the general 

 result may be shown diagrammatically, as in figure 4. 



Fig. 4.— a. Diagram of total distances and direc- 

 tions of movement in field of seppa cotton; B. 

 Approximate outline of present weevil-infested 

 area in the United States (original). 



