In the examination of my last season's collections of Hypena scabra (scabralis, Guen.,) and “H. erectalis,” for sexual determinations, I was surprised to find of the former, only the male represented. and of the latter, only the female. Collections of each having been made during the same period of time (from September 1st to September 24th) and at the same place (the wall and ceiling of the piazza of my residence)– such a remarkable occurrrence seemed to be so removed from accident, and inexplicable from any difference of sexual habits, that I was led to suspect the identity of the two species.