Let us, once April is here, detach and lay open this strange appendage. It is hollow, and full of an incomparable downy wadding; no feather-bed or eider-down could boast of so fine, so white a filling. In the midst of this magnificent eider-down some ovoid beads are scattered, some white and others tinged with a ruddy brown. These are the eggs. The new-born insects are swarming amongst them, higgledy-piggledy; some are bare and brown, some are more or less speckled with white, according to the more or less advanced state of the coat. On the other hand, let us watch the Dorthesia idly roaming about the spurge. At long intervals we shall see emerging from the orifice at the end of the padded pocket a young Louse, handsomely clad, and nimble in his movements, who chooses his place beside his mother and settles down, plunging his bill into the juicy bark. He will not stir again until the well is dry. Others follow him from day to day; and this goes on for months on end! If we were guided only by these observations we should conclude that the mother was viviparous, given to dropping, here and there, living offspring, all ready dressed. Nothing of the kind: we have just found in the thickly-quilted pocket both eggs and young. Moreover, the laying and hatching of the eggs may be witnessed without difficulty. In a glass tube provided with a sprig of spurge I segregate a few mothers whose terminal wallet I have removed. Laid bare, the insect’s hind-quarters have no further secrets from us; I see, sprouting from them, a sort of white mildew, like an unshaven beard. This is the waxy secretion that sprouts from the insect’s hind-quarters, producing, instead of tassels, filaments of extreme fineness. It is thus that the down which fills the wallet must be produced. Presently, in the midst of this tuft of down, an egg appears, like those which we obtained by breaking into the maternal treasury. This method enables me to estimate the size of the clutch. Two Dorthesiæ stripped bare behind and isolated, with provisions, in a glass tube, produced, in thirteen days, thirty eggs, or fifteen apiece, or rather more than one egg daily. As the process of laying continues for nearly five months, the total number of eggs for a single mother must be nearly two hundred. The eggs hatch in three or four weeks’ time. The hatching is announced by a change in the colour of the egg, which from white becomes a bright reddish-brown. On leaving the egg-shell the infant Louse is reddish-brown and absolutely naked. Its appearance is that of a very tiny Spider, the more so as its long antennæ look very like a fourth pair of legs. Before long, four longitudinal rows of tiny white tufts appear on its back, with bare spaces between them. This is the beginning of the waxen mantle.