none The results of the nocturnal periodicity of Opius incisi caught by a light trap placed at the Crop Research Farm, University of Burdwan (India) are incorporated in this paper. During one year of weekly samples, 27441 individuals with a female male ratio of 6.79:1 exhibited well defined nocturnal activity. Larger numbers appeared in March and August than other months and this was probably due to host distribution and favourable weather conditions prevailing in those two months. Among the five periods, maximum size and distribution pattern exhibited by O. incisi correlated with the hours of early midnight and declined exponentially until dawn when the individuals disappeared abruptly. This pattern of distribution ensured effective selection of the species to the preferred period and avoidance of the critically unpreferred ones.