Whether at home or abroad, whether passing along the public highway or visiting a friend, it was enough for an insect to appear to capture and retain his attention without regard for the circumstances and without a thought as to what might be said of him. On one occasion a Pelopæus, that is, a Potter-wasp (πηλοποίος) holding her pellet of mud in her jaws, came to his fireside one washing-day, seeking access to the nest which she was building behind the breast of the fireplace. More anxious about the Wasp than about the washing, he controlled the fire so that it should not too greatly incommode the little mason by eddies of smoke or flame, and for two good hours he followed the coming and going of the Pelopæus, and the progress of her nest-building. This was in the early days of his Avignon professorship. [50] Another day it was once again the strange mud-worker which attracted his attention, not in his own house this time but in the kitchen of Roberty, one of the chief farmhouses on the outskirts of Avignon. Returning to dinner from their work in the fields, the farm hands had hung, on pegs driven into the wall, one his blouse and another his hat. While they were devoting their attention to the soup, the guest had his eyes fixed upon the Pelopæi which came prowling about the men’s clothes and found them so well adapted to their needs that they began to build their nests upon them. Unfortunately for the builders and the spectator, the men soon rose from the table and shook their belongings, dislodging masses of mud already as large as an acorn. Ah! If he had been the owner of those garments, how gladly he would have allowed the Pelopæi to work their will, in order to learn the fate of a nest built upon the shifting surface of a smock-frock. [51] The unavoidable limitations imposed by observations undertaken at home are not more disappointing to the investigator than the possible disturbance caused by passers-by should he attempt to watch the insect on the public highways. Here is an example. The professor, on one of his “days off,” is quietly strolling along a narrow footpath on the banks of the Rhône: A Yellow-winged Sphex appears, hopping along, dragging her prey. What do I see? The prey is not a Cricket, but a common Acridian, a Locust! And yet the Wasp is really the Sphex with whom I am so familiar, the Yellow-winged Sphex, the keen Cricket-huntress. I can hardly believe the evidence of my own eyes.