Up to some sixty-five years ago, this species (Plate 46, Figs. 1 [male], 2 [female]) seems to have flourished in a wild state in the fens of Norfolk and Cambridgeshire, and also in Huntingdonshire. Just how long it had been common in those localities history does not inform us, but about 1792 Donovan was unable to obtain a native specimen to figure. Stephens, however, writing in 1828 states that at that time it abounded in the Huntingdonshire fens. "It is said," he remarks "to have been introduced into Britain by eggs imported by Mr. Collinson, but the abundance with which it occurs near {104} Whittlesea, and the dissimilarity of the indigenous specimens (which are invariably paler, with stronger markings) to the foreigner, sufficiently refute that opinion." There appears to be no doubt that some time near 1840 the Gipsy moth began to decrease in numbers, and that about 1850 it had almost or quite ceased to exist, as a wildling, in England. At the present time, and probably since the date last mentioned, the species has been semi-domesticated, and so reared year by year, at first possibly direct from the original wild stock, but afterwards from fresh stock derived from eggs of foreign origin. Futile attempts have been made to re-establish the species in various parts of England, and also in Ireland. Such failure is curious, seeing that in America the accidental introduction of a few moths has resulted in the species becoming so numerous that at least one state has been expending thousands of dollars in endeavouring to destroy it. The eggs are laid in batches and covered with the down-like scales from the anal tuft of the female. The caterpillar hatches in April, and in warm weather feeds up pretty quickly. It is grey, covered with black dots and fine marks; the hairs arising in spreading tufts from the raised warts, are longer on the sides than on the back; these warts on the back on each side of the pale central line are bluish on rings one to five, and reddish thence to eleven. Head, pale brown marked with black. Feeds on the foliage of most fruit trees, also on oak, elm, sallow, hawthorn, and sloe. Chrysalis rather hairy, brownish in colour, in a fairly strong silken cocoon, which is spun up in any suitable angle. The moths appear in August, and there is a striking difference in the size and coloration of the sexes. The male is pale or greyish brown, lined and clouded with darker brown on the fore wings, and the female is whitish with brownish cross lines, and a black central V-mark on the fore wings. Distributed over the whole of the Palæarctic Region, except {105} the most northern, and, as adverted to, it has now become a pest in parts of North America. THE BLACK ARCHES (_Lymantria monacha_).