Dr. Packard describes Sphex ichneumonea as nesting in gravelly walks, where it digs to a depth of from four to six inches, using its jaws and fore legs to do the excavating. While the wasps that he observed completed the hole in half an hour, ours was actually at work a little over four hours. Her nest, as is shown in the drawing, measured seven and one half inches to the beginning of the pocket, which was three quarters of an inch wide by one and one half inches long. The yellow–winged Sphex, a native of France, was found by Fabre to take several hours to make her nest, working in hard ground; while another species, also studied by this observer, dug in soft earth, either in the ground or in the accumulations on the roofs of buildings, and completed her work in fifteen minutes at the most. These variations in the habits of closely related species should be carefully studied in any attempt toward an explanation of their instincts. Fabre’s account of the genus Sphex, as it appears in France, is most interesting. He says that the yellow–winged species, living in colonies, first digs her nest and then secures her cricket, which is brought, on the wing, to the neighborhood of the burrow, the last part of the journey being accomplished on foot. The cricket is dragged by one of the antennæ, and is not left until the nest is reached. It is then placed so that the antennæ reach precisely to the opening, and there it is left while the wasp descends hurriedly into the depths of the burrow. In a few seconds she reappears, showing her head outside, seizes the antennæ of the cricket, and drags it below. These manœuvres are repeated with a striking degree of invariability.