Greenhouse and laboratory studies showed that each instar and adult of tarnished plant bug (TPB),Lygus lineolaris(Palisot de Beauvois), may feed on eggs and the first three instars ofHeliothisspp. Under greenhouse test conditions, significantly moreHeliothisspp. eggs were destroyed in a 24-h period by third- and fourth-instar TPB than by adult TPB. However, adult TPB preyed on significantly larger numbers of second- and third-instarH. virescens(F.) larvae during 24- and 48-h periods than any of the five instars. Under laboratory conditions, significantly higher percentages ofHeliothiseggs were destroyed in 24 and 48 h by the TPB adult and by each instar, two through five, than were destroyed by the first instar.