We have studied wasps for a number of years, and we feel that we are on terms of more or less intimacy with many of the species, but never before have we known one to work after day was done. We have often gone out with a lantern at bedtime for a tour of inspection among our nests, and have always found the inhabitants quiet and presumably asleep. The social wasps are very industrious, but during the hot nights of July they are to be seen clustered together on the outside of their paper nests in deep repose; and although the Vespa wasps that nest in the ground sometimes come home late in the twilight, we have never seen them work after it was really dark. Polistes fusca may be said to share our cottage, so thickly does she hang her combs under the shelter of our porches, and from observations taken at all hours we know that she is quiet through the night. Sir John Lubbock, in “Ants, Bees, and Wasps,” speaks of the great industry of wasps. He has known them to work from early morning until dusk without any interval for rest or refreshment; but here was our little Crabro toiling from three in the afternoon of July twenty–seventh, through that night and the day and night following until nine o’clock on the morning of the twenty–ninth,—a period of forty–two consecutive hours with one intermission of ten minutes on the morning of the twenty–eighth. Surely she takes the palm for industry, not only from other wasps, but from the ant and the bee as well. [Illustration: NEST OF C. STIRPICOLA]