Between 2 and 3 o'clock on the afternoon of Oct. 11, 1904, I observed remarkable flight of “Water Boatmen” at St. Paul, Minn. Thousands of them were flying hither and thither over several asphaltpaved streets, which had just been watered, and on which the sun was shining; the temperature was about 60°F in th shade, the sky was clear, and there was no wind. The insects evidently mistook the wet asphalt for water. Thousands of them alighted, and were held fast by the flim of mud until they died. About 5 o'clock I noticed on one street a struggling “Boatman” to every square inch of surface.