The protracted period of egg-laying, which continues for four months or more, the comparatively quick hatching, and, finally, the gradual exudation of the Louse’s clothing, explain why white eggs and reddish-brown eggs, with naked youngsters and others more or less clothed, are found simultaneously in the maternal pouch. This pouch is a warehouse in which the Louse’s eggs are collected for months together. Inside the pouch, in the depths of its luxurious padding, the young Lice are born, grow up, and clothe themselves in wax before risking the dangers of the open. The mother gently carries them from twig to twig of the spurge without troubling herself as to those that emerge from her pouch. One by one, as they feel themselves strong enough, they migrate, when their time has come, to settle down in the neighbourhood. The exit from their home is always open; they have only to force their way through the barrier of down. The Narbonne Lycosa carries her family about with much less tenderness and security. There is no shelter on the back of the Gipsy Spider, no safeguard against falls, which are frequent in such a scramble. The Dorthesia, more happily inspired, makes a box of the skirts of her mantle and a downy bed of her caudal tufts. To find an equivalent method we must go back from the Spurge-louse to the first-born of the Mammifers—Kangaroos, Opossums and others—who rear their young in a pouch formed by a fold of the skin of the abdomen. Coming before its time, the shapeless embryo fixes itself on the teat and completes its development in the maternal pouch or marsupium. Let us make use of this term to denote the Dorthesia’s pouch. There is a great similarity between the two wallets, although the insect is superior to the mammal in this respect: Life often begins with excellence in the lowly and ends with mediocrity in the strong. In the original device of the marsupium a Louse has done better than the Opossum. With the object of following the history of my insects more conveniently than was possible under the blaze of the sun by the roadside, I placed before one of my study windows a fine clump of spurge transplanted into a capacious flowerpot. As a result of my diligence the plant was populated during the course of March by three or four dozen Dorthesiæ, all wearing more or less fully developed marsupia. My experiment in the domestication of plant and insect was extremely successful: the spurge did well, so its inhabitants prospered also.