These excursions into the world of the fields, the delight of his youth and his earliest childhood, were henceforth to form the first item on his programme of studies. Mathematics were dropped, as Moquin-Tandon had advised. Physics and chemistry were put in their proper place, in the teaching of the lycée, and the whole of the young professor’s free energies were expended upon the research work of the naturalist. Necessarily limited by his occupation as a teacher, his investigations could not at ordinary times extend beyond the neighbourhood of Avignon. One of his favourite localities for observation, by reason of its nearness and its entomological wealth, was the table-land of Les Angles, opposite the town on the right bank of the Rhône. Morning or evening, he made quick work of crossing the river and climbing the cliff which divides it from the barren table-land which he calls his “little Arabia Petræa.” Presently his Thursdays and holidays were devoted to more distant and more prolonged observations. His steps took him, by preference, down-stream from Avignon, along the right bank of the Rhône, opposite the embouchure of the Durance, to a spot known as the Bois des Issarts. Not that he was drawn thither by the mossy carpets or the twilight of lofty forest trees which form the charm of our woodlands. The burning plains where the Cicada shrilled and the olive flourished know nothing of these delightful retreats, so full of shadow and coolness. Here is Fabre’s own description: The Bois des Issarts is a coppice of holm-oaks no higher than one’s head and sparingly distributed in scanty clumps which, even at their feet, hardly temper the force of the sun’s rays. When I used to settle myself in some part of the coppice suitable for my observations, on certain afternoons in the dog-days of July and August, I had the shelter of a large umbrella. If I neglected to furnish myself with this embarrassing adjunct to a long walk, my only resource against sunstroke was to lie down at full length behind some sandy knoll; and, when the veins in my temples were throbbing to bursting point, my last hope lay in putting my head down a rabbit-burrow. Such are one’s means of keeping cool in the Bois des Issarts. What was there to draw him and retain him in such places, so unpropitious for the holiday of a professor on vacation? Ah! they are the favourite resort of the Bembex, one of his favourite insects. “A blazing sun, a sky magnificently blue, sandy slopes to dig in, game in abundance to feed the larvæ, a peaceful spot hardly ever disturbed by a passing step”: all things combined to attract the digger-wasp to such localities.