In 1855 M. de Chavannes reared this species in the open air, near Lausanne, in Switzerland. This treatment succeeded perfectly, without any degeneration, for many years. It, however, died out at last, from the effects, perhaps, of too great a difference in the climate, or from those accidents, still so little understood, to which even the insects of our own country are subject. This was unfortunate, as this species is one of those whose acclimatisation in Europe is the most to be desired, for it would render great service to the cultivators of silk. It remains for us to speak of two other species, which are very important, inasmuch as their domestication in Europe is now an accomplished fact. We mean the _Attacus_ or _Bombyx_ of the Ailanthus, and also that of the Castor-oil plant. [Illustration: Fig. 227.--Cocoon of Attacus (Bombyx) Mylitta.] Every one has heard of the Ailanthus silkworm (_Attacus_ [_Bombyx_] _Cynthia_), whose acclimatisation in Europe has been materially assisted by the admirable and persevering efforts of M. Guérin-Méneville. The Ailanthus worm is a native of Japan and of the north of China. It was brought over in 1858 by Annibale Fantoni, and sent to M. Guérin-Méneville by MM. Griseri and Colomba, of Turin. When it is nearly full-grown it is emerald green, with the head, the feet, and the last segment of a beautiful golden yellow, and has black spots on each segment. This worm, in its full-grown state, is represented by Fig. 228; in the same figure are also represented the eggs and the cocoon. The moth has the abdomen yellowish underneath, with little white tufts. Its wings are traversed by a white band, which is followed exteriorly by a line of a bright rose; each wing is also marked by a lunula or crescent-shaped spot. In 1858 M. Guérin-Méneville presented to the Académie des Sciences of Paris the first moths and the first eggs laid in France of the _Attacus Cynthia_. This able entomologist demonstrated very soon afterwards--1st, that the caterpillars of this insect can be reared in the open air, and with scarcely any cost for management; 2ndly, that it produces two crops a year in the climate of Paris and the north of France; 3rdly, that the cultivation of the Ailanthus, or the false Japan varnish tree, on which this insect lives, is easy even in the most sterile soil. [Illustration: Fig. 228.--Eggs, larvæ, and cocoons of Attacus (Bombyx) Cynthia.]