Seasonal abundance and activity ofSitona hispidulus(F.) adults were monitored from June 1976 to August 1978 in alfalfa and red clover. A sharp rise in density followed by an equally sharp decline occurred during June and early July. Emergence from pupae occurred during June. Cumulative emergence data indicated that this increasing density was due to accumulation of the adults emerging from the pupae. Directional pitfall trapping indicated that the decline density was due to emigration of adults into the field borders by crawling. After this decline in density and the crawling activity stopped, the density remained about the same from late July through late August. This corresponded with the relative inactivity of the oversummering adults. From late August until late October the adults were active again, exhibiting crawling activity and a flight period. Directional pitfall trapping and sticky trapping indicated that movement, both into and out of the field, occurred during this period.