The seasonal emergence periods from the soil of adult lesser chestnut weevil, Curculio sayi (Gyllenhal), was assessed for three years at a site in mid-Missouri using wire cone emergence traps. Two additional trap types, Circle and pyramid, were used to assess the timing of adult movement into the trees. The trap data indicated there were two distinct adult emergence periods, the first occurring in early-May and the second beginning late-August. This is in contrast to previous studies that have reported C. sayi as having only one seasonal emergence period (which occurs in the spring). Our study also examined the underground development of C. sayi. The data showed that, after leaving the chestnut, most larvae burrow to a soil depth of 7.5–15 cm where they remain for at least 19 mo, and that the weevils have an overall life cycle (egg hatch to adult emergence) of about 20–21 mo.