On page 54 of the current volume of the Canadian Entomologist, I called attention to the sudden and almost total disappearance of this species at Wooster, Ohio, where it had for several years been excessively abundant, even up to the latter part of August and early September of last year, 1899. This abrupt termination of the period of activity was at the time attributed to the effect of a parasitic species, Ichneutes, sp. ?, which had in the meantime become also excessively abundant.