for her to grip it by any other. To understand that she can take a leg instead of an antenna is utterly beyond her powers. She must have the antenna, or some other string attached to the head, such as one of the palpi. If these cords did not exist, her race would perish, for lack of the capacity to solve this trivial problem. EXPERIMENT II The Wasp is engaged in closing her burrow, where the prey has been stored and the egg laid upon it. With her front tarsi she brushes her doorstep, working backwards and sweeping into the entrance a stream of dust which passes under her belly and spurts behind in a parabolic spray as continuous as a liquid spray, so nimble is the sweeper in her actions. From time to time the Sphex picks out with her mandibles a few grains of sand, so many solid blocks which she inserts one by one into the mass of dust, causing it all to cake together by beating and compressing it with her forehead and mandibles. Walled up by this masonry, the entrance-door soon disappears from sight. I intervene in the middle of the work. Pushing the Sphex aside, I carefully clear the short gallery with the blade of a knife, take away the materials that close it and restore full communication between the cell and the outside. Then, with my forceps, without damaging the edifice, I take the Ephippiger from the cell, where she lies with her head at the back and her ovipositor towards the entrance. The Wasp’s egg is on the victim’s breast, at the usual place, the root of one of the hinder thighs: a proof that the Sphex was giving the finishing touch to the burrow, with the intention of never returning. Having done this and put the stolen prey safely away in a box, I yield my place to the Sphex, who has been on the watch beside me while I was rifling her home. Finding the door open, she goes in and stays for a few moments. Then she comes out and resumes her work where I interrupted it, that is to say, she starts conscientiously stopping the entrance to the cell by sweeping dust backwards and carrying grains of sand, which she continues to heap up with scrupulous care, as though she were doing useful work. When the door is once again thoroughly walled up, the insect brushes itself, seems to give a glance of satisfaction at the task accomplished, and finally flies away.