M. Guérin-Méneville showed still further that _ailantine_, the textile matter furnished by the cocoon of the Cynthia, is a sort of floss silk holding a middle place between wool and the silk of the mulberry-tree worm, and which, as it can be produced at scarcely any expense, would be very cheap, and would serve for the fabrication of what are called fancy stuffs, for which ordinary floss silk is now used. In 1862 M. Guérin-Méneville sent in a Report to the Minister of Agriculture on the progress of the cultivation of the Ailanthus, and of the breeding of the silkworm, which was reared in the open air on this tree. He mentions, in his Report, the rapid development of the cultivation of the tree in France, the great number of eggs of the Ailanthus silkworm sold, the foundation of a model silkworm nursery at Vincennes, and, this one great point gained, that they had found out the way of unwinding the silk from the cocoons of the _Cynthia_ in one unbroken and continuous thread. Till then European industry had only succeeded in drawing from the cocoons of the Ailanthus silkworm a floss silk, composed of filaments more or less short, obtained by carding, and unable to produce, when twisted, anything better than floss, that is to say, refuse silk. It is to the Countess de Vernéde de Corneillan, on the one hand, and to Doctor Forgemot on the other, that the merit is due of having obtained an unbroken thread of silk from the cocoon of _Attacus Cynthia_. A monograph on the Ailanthus silkworm appeared in 1866 under the title, "L'Ailante et son Bombyx, par Henri Givelet."[67] It is a complete account of all the results obtained up to the time, both as regards the rearing of the silkworm and also as regards the cultivation on a large scale of the Ailanthus, or false Japan varnish tree.[68] [67] In 8vo, avec plans et planches coloriées. Paris, 1866. [68] A work by M. Guérin-Méneville on the same subject, entitled, "Education des Vers à Soie de l'Ailante et du Ricin," in 12mo., Paris, 1860, may also be consulted. [For a full account of successful experiments carried on in England, see Dr. Wallace's essay in _The Transactions of the Entomological Society of London_, 3rd series, vol. v., pt. 2; Longmans and Co.--ED.] The Castor-oil Plant Silkworm (_Attacus_ [_Bombyx_] _ricini_) is a species very nearly akin to the Ailanthus worm, perhaps only a variety, and comes from India. The silk which it produces is very similar in every respect to that of the _Cynthia_. The rearing of this worm could never attain to any great importance in France, on account of the necessity there is of renewing the plantations of the castor-oil plant each year. It would, however, afford an additional source of income to the farmers in the south of France, who cultivate the castor-oil plant with a view to selling its seeds, which are much used in pharmacy.