coolest apartment, so the height of the tower in question seems to be an additional protection against the rays of the scorching sun. After it has deposited its egg at the bottom of the excavation, the sand-wasp sets out on a foraging expedition, and hunts about until she finds certain green caterpillars. Seizing upon one of these she flies with it to her mine, and then returns for more prey. After collecting about a dozen of these helpless beings, fixing them so that they are hopeless captives inside her dark prison, she bids farewell to the egg, for the future well-being of which she has thus assiduously provided. She takes down her tower of stones, and, with the materials which composed it, fills up the entrance to the cell, thus shutting in both the prisoners and their future devourer in a common dungeon, there to await the changes which time will inevitably bring about. Let us speak now of eggs carefully deposited by other insects in galleries and excavations made into timber. The insects which thus act have been called by the fanciful title of carpenter-bees, in allusion to the drilling process by which they penetrate the wood. A highly interesting spectacle it is, in truth, to see one of these pigmy carpenters at her work, and, fortunately, some of the species are not very uncommon in our gardens. Spring is the season when she commences her labours. She reconnoitres about for a proper piece of timber for some time, and exhibits great discrimination in the selection of a suitable place for establishing herself and for the nurture of her progeny. Strange to say, she will not select living wood, such as the trunk of a tree, but generally prefers wood which has already begun to decay, as if fully aware that such wood was likely to give her much less trouble in boring than any other. She also selects a piece of wood placed in some sunny and genial position, with a view to the development and comfort of her progeny. This important point being settled to her mind, she next sets about the work. Well may Réaumur exclaim, "Truly the labour she has undertaken demands strength, courage, and patience!" [Illustration: _Carpenter-Bee._] [Illustration: _Mandibles of the Carpenter-Bee._]