Erythroneura lawsoniRobinson (Homoptera: Cicadellidae), specific to sycamore, was studied in east-central Illinois in 1972, under both laboratory and field conditions. Adult. females laid 4–6 eggs/week during a 4–5 week oviposition period. Eggs hatched within 15 days, and 5 nymphal instars followed, with a mean development time of 3–5 days/instar. Mean generation time was 41 days, and 4 partially overlapping generations occurred in 1972.This species coexists with 4 other leaf-sucking insects on sycamore:Empoasca fabae(Harris),Empoa platanaChristian (Cicadellidae),Corythucha ciliata(Say) (Tingidae) andPlagiognathus albatus(Van Duzee) (Miridae); the last 3 species are specific to sycamore. The species show differences in temporal and spatial exploitation of sycamore leaves, so that overlap of feeding niches is small.Empoasca fabaefeeds on main viens,Erythroneura lawsonion the leaf blade close to larger veins,Empoa platanaon the leaf blade distant from veins, and the maximum niche overlap seen between these species is 38%.C. ciliatafeeds on the whole area of the leaf blade, and thus overlaps other species extensively, 84% forErythroneura lawsoniand 80% forEmpoa platana. But overall overlap, when both time and space are considered, is reduced to a maximum of 63% betweenC. ciliataandE. lawsoni, and to much less (0–39%) for other species combinations.The sycamore leaf offers a mosaic of microhabitats which allows niche diversification and specialization in the leaf-feeding guild.