Technical Abstract: Boll weevil movement, measured by pheromone-baited traps, was investigated relative to the development of cotton in selected (core) cotton fields. In general, more boll weevils were captured at sites away from than near cotton fields. High numbers of boll weevils were captured up to five miles from cotton. Boll weevil trap captures declined at all sites as the growing season progressed; however, the decline was much more rapid near cotton. Boll weevils were captured at all locations during the entire cropping season indicating that overwintered boll weevils may enter cotton over the entire cropping season or that there is a continuous movement of boll weevils between cropped and uncropped areas. The percentage of total number of boll weevils captured before first one-third grown square ranged from 95 percent at Munday, Texas, to 50 percent in Tampico, Mexico. Evidence is presented which suggests that a portion of the F1 boll weevil population leaves cotton and moves to remote areas although cotton is near the peak fruiting period.