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.
The fact is, that _Yamamai_ is a difficult moth to rear in a country like this, where in early spring the temperature varies so much; but that success is possible, I am convinced.