I have given this extract, word for word, as it stands in the columns of the Tribune, because it contains more blunders of one kind or another than I remember ever to have seen in so many words. Cecropia is certainly not very particular as to its food, but it is not an oak feeder. Cynthia will thrive on nothing except ailanthus, though it will eat one or two other things, but not oak. The Yamamai, on the other hand, will eat oak, indeed it is its natural food; but Mr. Warren errs greatly when he says that it will feed on mulberry. The last clause of the sentence, which says that cocoons of Pernyi are nearly as good as those of worms fed on mulberry leaves, must be a sort of entomological joke, of which the point is not discoverable by me, so I pass it over.
I do not, however, notice this report on account of its grammatical and entomological mistakes. It is because of the evil effects it may, and probably will, have on amateur silk culturists, that I notice it; for most assuredly, failure will be the result of all attempts to produce silk cocoons by feeding the caterpillars of the different moths on the food prescribed by Mr. Warren. Any patriotic, money making farmer, who believes in the Tribune, purchasing Yamamai eggs and setting his worms to feed upon mulberry, which they refuse to eat, and consequently, all die, will probably give up silk culture as being nothing more or less than a humbug. And thus the cause is injured.
For several years past, I have made some experiments in the rearing of the silkworms, giving the result of my experience in the first year in Vol. II., page 311, of the American Naturalist; and of a subsequent year in the Entomologist, for November, 1869.
The paper in the Naturalist is devoted to my experiments with the ailanthus silkworm, Samia Cynthia (G. & R.), a naturalized species from the East. In that paper, I have said all that is necessary to say at present, on that species, except perhaps that I am further convinced, from the inspection of samples of sewing and other silks, made from the cocoons of Cynthia, that one day it will be reared very extensively in the United States. It is perfectly hardy, is double brooded, and may be reared by any one possessed of a few acres of land, which may be good enough for growing ailanthus trees, but not good enough to grow any thing else. The labor of a few old men, or women, or even children, is sufficient for the purpose. The cost is therefore trifling.
The objection to the cultivation of Cynthia is that the cocoon cannot be reeled. But it can be carded, and if the Chinese can make excellent silk goods from it, why cannot we? I suspect, too, that Cynthia silk can be worked in with cotton, or, perhaps, woolen goods, adding to their beauty and durability (for it is indestructible in wear), and thus open up branches of manufacture hitherto unknown.
For manufacturers of coarse goods, I have no doubt that the silk from our native silk moths, Cecropia and Polyphemus, may be used. Indeed, I believe that M. Trouvelot is of opinion that Polyphemus may fairly enter into competition with Bombyx mori, the ordinary mulberry silkworm. The worm, however, is rather difficult to rear.
In reference, however, to Bombyx mori, it is well known that the silk crop in France and Italy has been reduced greatly, and the price of silk goods consequently enhanced, by prevalence of disease among the worms. So much is this the case, that silk breeders have been obliged to look around for some silk-producing moths whose products may, at any rate, supplement the deficient crop. Cynthia, as already mentioned as one of these, and two others mentioned by Warren in the Tribune reports above adverted to, are at present the subjects of experiment.
My article mentioned before as appearing in the American Entomologist is mainly devoted to my experiments, and those of my correspondents, with Yamamai, which, as I said before, is an oak feeder. In Japan, which is its native country, it feeds, in its wild state, on Quercus serrata. Whether that oak be found in America, I do not know, but it is of little importance, as the worm will feed on almost any species of oak, although I think that it prefers white oak. The importance of acclimatizing new species of silk moths is of so much prospective importance, that I shall devote the remainder of this article to the consideration of whether Yamamai and Pernyi may not be naturalized here. Any one, who happens to have the number of the Entomologist containing the article above alluded to, may find it worth while to read it, but as many persons may not be able to obtain that number, I will here repeat the substance of my remarks, adding as much new matter as subsequent experience has afforded.
The silk from the Yamamai being considered superior to that produced by any other of the substitute silk moths, great efforts have been made in Europe to acclimatize it; but, it must be confessed, hitherto with but slight success. There are exceptions, however, particularly among amateurs in Germany, sufficient to show that success is possible. The Baron de Bretton raises about 27,000 cocoons annually.
In this country but little has been done, or attempted, and that little has not been very successful.