Predation on eggs of the cotton bollworm, Helicoverpa zea Boddie, and the beet armyworm, Spodoptera exigua (Hübner), in south Texas cotton was measured using direct observation of sentinel eggs to identify key predators and partition nocturnal and diurnal sources of mortality. Predation was more commonly observed at night. The most frequently observed predators were nocturnally active and were dominated by cursorial spiders (primarily Hibana futilis (Banks)) and the red imported fire ant, Solenopsis invicta Buren. Most predators were active during the day or at night but not both. Many of the nocturnally active predators have not previously been considered important predators of lepidopteran eggs.