I was, however, not the only one to profit by the shade of my umbrella; I was generally surrounded by numerous companions. Gad-flies of various species would take refuge under the silken dome, and sit peacefully on every part of the tightly-stretched cover. I was rarely without their society when the heat became overpowering. To while away the hours when I had nothing to do, it amused me to watch their great gold eyes, which shone like carbuncles under my canopy; I loved to follow their solemn progress when some part of the ceiling became too hot and obliged them to move a little way on. One day, bang! The tight cover resounded like the skin of a drum. Perhaps an oak had dropped an acorn on the umbrella. Presently, one after the other, bang, bang, bang! Can some practical joker have come to disturb my solitude and fling acorns or little pebbles at my umbrella? I leave my tent and inspect the neighbourhood: nothing! The same sharp sound is repeated. I look up at the ceiling, and the mystery is explained. The Bembex of the vicinity, who all consume Gad-flies, had discovered the rich provender that was keeping me company, and were impudently penetrating my shelter to seize the flies on the ceiling. Things were going to perfection; I had only to sit still and look. Every moment a Bembex would enter, swift as lightning, and dart up to the silken ceiling, which resounded with a sharp thud. Some rumpus was going on aloft, where the eye could, no longer distinguish between attacker and attacked, so lively was the fray. The struggle did not last for an appreciable time: the Wasp would retire forthwith with a victim between her legs. Obviously this suddenness of attack, followed by the swift removal of the prey, does not allow the Bembex to regulate her dagger-play. [49] With ever-increasing accuracy, by the combined efforts of observation and experiment, that rich entomological material was amassed which was one day to serve for the erection of one of the finest and most enduring monuments of contemporary science. We should form but a very incomplete idea of the sort of work to which the future author of the Souvenirs began to devote himself at this early stage of his professorship were we merely to note his frequent visits to Les Angles and his long sessions beneath his umbrella in the Bois des Issarts. Apart from this favourite field of observation, the enthusiastic curiosity of the naturalist found scope for its exercise on every hand.