Feeding behavior of the nymphs of Leptocorisa chinensis Dallas (Hemiptera: Alydidae) on various poaceous (grass) species was investigated. The sequence of behavioral phases of the nymph on the food plant was as follows: antennation, rostrum extension, dabbing with the labium, rostrum placement on the plant surface, stylet penetration, and sustained ingestion. Observed behavioral phases of nymphs released on seed heads differed among three categories of plants: food grasses (including rice), nonfood grasses, and nongrasses (nonfood). The nymphs were able to discriminate food grasses from nonfood grasses before they penetrated with their stylets. On nongrasses, nymphs did not exhibit the feeding behavioral phases except for antennation. Nymphs also exhibited behavioral phases such as antennation, rostrum extension, and dabbing with the labium, on paper strips treated with methanol extract of food grasses, but not with extract of nonfood grasses and nongrasses. These results suggest that chemical cues exist in food grass species.