For that matter, my want of success might well be due to another cause. The Pelopæus certainly is not rare in our southern towns; nevertheless she prefers the peasant’s smoky house to the townsman’s white villa. Nowhere have I seen her so plentiful as in my village, with its tumbledown cottages guiltless of rough-cast and burnt yellow by the sun. My hermitage is not quite so rustic as that: it is a little neater and cleaner; and there is nothing to show that my visitors did not forsake my kitchen and my study, both too sumptuous in their opinion, to go and settle somewhere near in lodgings more to their taste. And so the eagerly desired colonists, who were to have peopled my workroom crammed with books, plants, fossils and entomological cemeteries, took their departure, scorning all that scientific luxury; they went away in search of some dim chamber with a solitary window sporting a sprig of wall-flower in an old, cracked stew-pot. Felicities like that are reserved for the humble; and I am therefore reduced to what I have gained by an occasional piece of good luck, irrespective of any efforts of mine. The little that I have seen, in one direction and another, is after all sufficient evidence of the pluck of the Pelopæus, who, to reach her nest built in a corner of the hearth, at times passes through a cloud of steam and smoke. Would she dare to cross a thin sheet of flame? That was what I had proposed to see, if my attempts to acclimatize her in my home had met with any success. It is obvious that, in displaying a marked predilection for the chimney as her abode, the Pelopæus is not seeking her own comfort: the site chosen means work and dangerous work. She seeks the welfare of her family. This family then, in order to prosper, must require a high temperature, such as is not demanded by the other Wasps or Bees, the Chalicodoma and the Osmia, for instance, who find sufficient shelter under a mortar dome or in the hollow of an exposed reed. Let us see what temperature the Pelopæus finds to her liking. On the side-wall, under the chimneypiece, I hung a thermometer over a Pelopæus-nest. During an hour’s observation, with a fire giving out a moderate heat, it fluctuated between 95° and 105° F. This temperature, it is true, does not remain the same during the long larval period; on the contrary, it varies greatly, according to the season of the year and the time of day. I wanted something better and I found it on two occasions. My first observation was made in the engine-room of a silk-factory. The back of the boiler reached nearly to the ceiling, the space between being barely twenty inches. It was against this ceiling, right above the huge cauldron, which was always full of water and steam at a high temperature, that the Pelopæus-nest was fixed. At this spot the thermometer marked 120°. This degree of heat was maintained all through the year; it was only at night and on holidays that it decreased.