A behavioral ethogram for feeding and nonfeeding behaviors of Lygus hesperus Knight, the western tarnished plant bug, was developed using third instars on host and nonhost plants, as well as an artificial diet. Individual insects were simultaneously recorded with an AC electronic monitoring system and a time-lapse video cassette recorder. The electronic monitor provided information on the various stylet penetration behaviors exhibited, whereas the video was used in evaluating nonfeeding and surface exploration behaviors on plants and stylet activities in the diet. From these recordings, seven distinct feeding waveforms and over 20 nonfeeding behaviors were described. Artificial diet correlations were performed to verify ingestion and possible salivation activities during other waveforms. Some behaviors were found only to occur on particular substrates. These included the release of a salivary bubble following a period of feeding on the artificial diet and a continual labial dabbing behavior on mature cotton plants. An association was observed between ingestion and specific positions of the labium and antennae during the construction of an ethogram. A subsequent experiment was conducted that confirmed this relationship on mature and immature cotton.