A sex pheromone has been characterized in only one species of Miridae (Heteroptera). Female Campylomma verbasci produce two butyrates, which, together, attract males to traps (Smith et al. 1991). Little new knowledge of the chemistry of Lygus species female-produced sex pheromones has been gained since the review of Aldrich (1988). While some sexual dimorphism was reported in volatiles recovered from Lygus lineolaris, the tarnished plant bug of the eastern U.S., no such dimorphism was found in females of the western tarnished plant bug, Lygus hesperus. Field tests of candidate materials from the volatiles of each species have failed to reveal a useable attractant for males. Although a good deal is known about the pheromone biology of these Lygus species, the development of reliable bioassays has proven elusive. No behaviorally-active extracts of native materials have been obtained from either species. There are occasional instances in which excised portions of the last abdominal segments from virgin females have elicited upwind flight orientation and aggregation of conspecific males.