We used polymerase chain reaction (PCR) techniques to evaluate the detectability of intraguild predation of immature aphid parasitoids by lady beetles. Mitochondrial DNA from the parasitic wasp Lysiphlebus testaceipes Cresson was detectable within the gut of the convergent lady beetle, Hippodamia convergens Guérin-Méneville, by using PCR following intraguild predation of a parasitized greenbug, Schizaphis graminum (Rondani). Detection with PCR was possible as many as 16 hours post-feeding 100% of the time by using newly developed primers. Intraguild predation of L. testaceipes by coccinellids in fields of winter wheat, Triticum aestivum L., was common during the spring; the proportion of intraguild predators consuming L. testaceipes ranged from 0.667 to 0.871. Our findings justify the use of PCR as a tool to document intraguild pedation and may lead to more quantitative evaluations of the dynamics and consequences of this common ecological phenomenon.