The life cycle of Pachycoris klugii on its native host, Cnidoscoulus multilobus (Euphorbiaceae), is reported in detail for the first time. Egg, nymphs, and adults are described and illustrated. Extensive variation was observed in the color pattern of adults. Maternal behavior was related to egg parasitism, habitat and host plant phenology. The tachinid fly Trichopoda pennipes was observed parasitizing adults and the scelionid wasp Telenomus pachycoris parasitized eggs of P. klugii.