A prey-specific gut content enzyme-linked immunosorbent assay (ELISA) was used to identify predation of eggs of bollworm, Helicoverpa zea (Boddie), by Orius spp. in commercial cotton fields in Texas. Degradation of the egg protein began immediately after O. insidiosus fed on an egg. However, the protein antigen was detectable in the predator for approximately 10 h after feeding. The antigen retention time provided a conservative estimate of predation and insured that when predation was detected it occurred on the day predators were collected. The percentage of individual of Orius spp. that was positive by ELISA for the egg antigen varied throughout each growing season. The highest frequency of positive responses occurred before cotton bloom and after peak bloom.