WILD SILKS The ravages of pebrine and other diseases had the effect of attracting prominent attention to the numerous other insects, allies of the mulberry silkworm, which spin serviceable cocoons. It had been previously pointed out by Captain Hutton, who devoted great attention to the silk question as it affects the East Indies, that at least six species of Bombyx, differing from B. mori, but also mulberry-feeding, are more or less domesticated in India. These include B. textor, the boropooloo of Bengal, a large species having one generation yearly and producing a soft flossy cocoon; the Chinese monthly worm, B. sinensis, having several generations, and making a small cocoon ; and the Madrasi worm of Bengal (B. croesi), the Dassee or Desi worm of Bengal (B. fortunatus) and B. arracanensis, the Burmese worm—all of which yield several generations in the year and form reelable cocoons. Besides these there are many other mulberry-feeding Bombycidae in the East, principally belonging to the genera Theophila and Ocinara, the cocoons of which have not attracted cultivators. The moths yielding wild silks which have obtained most attention belong to the extensive and handsome family Saturnidae. The most im portant of the species at present (1940) is the Chinese tussur or tasar worm, Antheraea pernyi, which is an oak-feeding species, native of Mongolia, from which is derived the greater part of the so-called tussur silk imported into Europe. Closely allied to this is the Indian tussur moth, Antheraea mylitta, found through out the whole of India feeding on the bher tree, Zizyphus jujuba, and also on many other plants. It yields a large compact cocoon of a silvery grey colour, which Sir Thomas Wardle of Leek, who devoted a great amount of attention to the wild-silk question, suc ceeded in reeling. Next in promising qualities is the muga or moonga worm of Assam, Antheraea assama, a species to some ex tent domesticated in its native country.
The yama-mai worm of Japan, Antheraea (Sarnia) yama-mai, an oak-feeder, is a race of considerable importance in Japan, where it was said to be jealously guarded against foreigners. Its eggs were first sent to Europe by Duchene du Bellecourt, French consul-general in Japan in 1861 ; but early in March following they hatched out, when no leaves on which the larvae would feed were to be found. In April a single worm got oak-buds, on which it throve, and ultimately spun a cocoon whence a female moth issued, from which Guerin Meneville named and described the species. A further supply of eggs was secretly obtained by a Dutch physician Pompe van Meedervoort in 1863, and, as it was now known that the worm was an oak-feeder, and would thrive on the leaves of European oaks, great results were anticipated from the cultivation of the yama-mai. These expectations, however,
for various reasons, have been disappointed. The moths hatch out at a period when oak leaves are not ready for their feeding, and the silk is by no means of a quality to compare with that of the common mulberry worm. The mezankoorie moth of the Assamese, Antheraea mezankooria, yields a valuable cocoon, as does also the Atlas moth, Attacus atlas, which has an omnivorous larva found throughout India, Ceylon, Burma, China and Java. The Cynthia moth, Attacus cynthia, is domesticated as a source of silk in certain provinces of China, where it feeds on the Ailan thus glandulosa. The eria or arrindi moth of Bengal and Assam, Attacus ricini, which feeds on the castor-oil plant, yields seven generations yearly, forming loose flossy orange-red and sometimes white cocoons. The ailanthus silkworm of Europe is a hybrid between A. cynthia and A. ricini, first obtained by Guerin Mene ville, and now spread through many silk-growing regions. These are only a few of the moths from which silks of various usefulness can be produced; but none of these presents qualities, saving per haps cheapness alone, which can put them in competition with common silk.
A wild silk which has entered the market since the beginning of the loth century is Anaphe. It is found in West and East Africa. The worms combine to make large nests of cocoons with a strong outer protecting covering, tough as parchment. A peculiar and unpleasant quality of this species is the presence of hairs of a somewhat poisonous nature which bring out a rash on the skin when the nests are handled. Chemical treatment before handling has eliminated this trouble, but progress with the utilization of this silk is slow. It first began to attract attention in Germany in 1913 hut its experimental stage was held up until 192o. At first, the outer cover was thrown away and the internal cocoons were treated, but it has since been found that the outer cover is the more valuable and the internal cocoons hardly worth the trouble of working. Natives use the nests for the manufacture of their blankets but its economic usefulness in Europe has still to be proved. The systematic planting of the bush on which the Anaphe worm feeds would also be indicated if there is to be a constant and cheaper supply of this material.