Influences of food source, photoperiod, collection date, and time (hour within the diel cycle and day within the ovipositional period) on egg-laying of the pea leaf weevil,Sitona lineatus(L.), were used to evaluate ovipositional cycles in the laboratory. Ovipositional rhythms have two major divisions: a complete ovipositional rhythm and a diel ovipositional cycle. The complete ovipositional rhythm consisted of three levels: 1) second-degree polynomial curve, 2) 30-day cycle, and 3) daily oscillation and increase in amplitude of the daily oscillation as the ovipositional rhythm progressed. The diel ovipositional cycle was dominated by two general periods: increased oviposition (10 a.m.–9 p.m.) and decreased oviposition (12 p.m.–9 a.m.) with intervening transitional periods. The lack of a dark cycle affected the diel ovipositional cycle by reducing the magnitude of the afternoon peaks and the morning transition period. Type of food did not significantly affect the diel cycle or complete ovipositional rhythm. Melanization ofS. lineatuseggs started ca. 13 h after oviposition and was completed within 17 h at 21°C in constant light. A significantly slower melanization rate was noted for eggs of weevils fed alfalfa foliage than those fed pea foliage.