Not far from Avignon, on the right bank of the Rhône opposite the mouth of the Durance, is one of my favourite points for the observations about to be recorded. It is the Bois des Issarts. Let no one deceive himself as to the value of the word “bois”—wood, which usually gives the idea of a soil carpeted with fresh moss and the shade of lofty trees, through whose foliage filters a subdued light. Scorching plains, where the cicada grinds out its song under pale olives, know nothing of such delicious retreats full of shade and coolness. The Bois des Issarts is composed of thin and scattered groups of ilex, which hardly lessen the force of the sun’s rays. When I established myself during the dog days in July and August, I used to settle myself at some spot in the wood favourable for observations. I took refuge under a great umbrella, which later lent me most unexpected aid of another kind, very valuable too, as my story will show in good time. If I had neglected to equip myself with this article, embarrassing enough in a long walk, the only way to avoid sunstroke was to lie at full length behind some heap of sand, and when my temporal arteries beat intolerably, the last resource was to shelter my head at the mouth of a rabbit hole. Such are the means of getting cool in the Bois des Issarts. The soil, unoccupied by any woody vegetation, is almost bare and composed of a fine, arid, very light sand, heaped by the wind in little hillocks where the stems and roots of the ilex hinder its blowing about. The slope of such hillocks is generally very smooth, from the extreme lightness of the material, which runs down into the least depression, thus restoring the regularity of the surface. It is enough to thrust a finger into the sand, and then to withdraw it in order immediately to cause a downfall, which fills up the cavity and re-establishes the former state of things without leaving any trace. But at a certain depth, varying according to the more or less recent date of the last rains, the sand retains a dampness which keeps it stable, and lends a consistency allowing of slight excavations without roof and walls falling in. A burning sun, a radiant blue sky, sand slopes yielding without the least difficulty to the strokes of the Hymenopteron’s rake, abundant game for the larvæ, a peaceful site rarely troubled by the foot of the passer-by,—all unite here in this paradise of the Bembex. Let us see the industrious insect at work.