Scutellera perplexa (Westwood) was observed as a serious sucking pest of Jatropha curcas L. from Delhi and adjoining areas. As details were not previously available on its bionomics, studies were done between April 2007 and August 2009 under laboratory and field conditions. It remained active throughout the year and severe damage to foliage and developing fruits was observed between July and March. Population density was highest between September and November. The life cycle takes about 63.3±3.07 days: egg period lasted for 6.67±0.87 days with 98.87±2.24 per cent hatchability and nymphal durations of I, II, III, IV and V instar were 5.33±0.82, 7.95±0.68, 6.15±0.91, 7.54±0.76 and 9.69±1.18 days, respectively. A key to the identification of different instars is given.