We studied the phenology and the daily activity patterns of Pardosa milvina Hentz 1844 and Hogna helluo (Walckenaer 1837) in replicated soybean fields in southwest Ohio over three years (1994–1996) using pitfall traps. For the phenology study we established an array of five pitfall traps in 12 replicate 0.42 ha fields. These traps were either set for two days at two-week intervals (1994), or for three days at three-week intervals (1995 & 1996), over the field season from May–October on a total of 20 trap dates. We found that P. milvina was more common overall, and found evidence for one population peak per year. Numbers of H. helluo tended to be lowest in the earlier censuses, and we found evidence for one peak of male activity per year. The immature male and female, and adult female H. helluo were larger (based on carapace width) than the immature male and female, and adult female P. milvina on most trapping dates. For the circadian activity periodicity study we used two different drift-fence trap designs, both with dry-cup pitfall traps set for two or three days and checked at 12 h intervals. For three sampling periods in 1994 we found H. helluo to be more frequently trapped at night, and for two sampling periods P. milvina was more frequently trapped during the daylight hours.