OTHER SILKWORMS. It is supposed by sonic entomologists that the original wild silkworm from which descended the silkworm of commerce is a species known as Theophila Huttoni, which occurs in Japan, the Northwest Himalayas. and Assam. The moth is of the same size as that of Bombyx mori, is light brown in color, and has the characteristic markings on the wings. The larva almost precisely resembles the domestic silkworm, but has a pair of small black thorns on the back of each segment of the abdomen. It seems very unlikely, however, that this species could have been the ancestor of Bombys wort, since it lacks palpi, which are present in the Bombyx.
Oriental people have utilized the cocoons of a number of species of bombycid moths in the manufacture of silk goods. The so-called tussah, tusseh, or tusser silkworm is Antkerma niylitto, a species which occurs in China, India. and Ceylon. In Upper India this silk is extensively produced. and the cocoons are collected id the jungle districts by the Sahars and other half wild castes who live in such places. Other silk worms which are said to be used in the manu facture of tusseh silk are Anther-era pernyi, from China; Antheram Assama (Saturnia Perottetli and Antlicrtra mczankooria are synonyms of this species), a native of Assam. and there called `moonga' or `moogha ;' Antherma Roylei, from India ; Antherwa Helferi from Sikhim: Anthertra jour, from Java; AntheraTt Frithii. from Sikkim, Bhutan. and Darjeeling; and Antbercra larissa, from Java. The very large and beautiful Attacus atlas, from India, Ceylon, Burma, and Java, is also said to produce cocoons used in making tusseh silk.
The wild silkworms which have received the most attention in Europe, however, are An /hey-ow yama-mai, from Japan, eommonly known as the 'pima-mai' silkworm: Anthenra pernyi, from China: and Philosanzia cynthia, from Japan, China, the Himalayas, Assam. and Java, which has been introduced into Europe and which has been acclimatized in the Eastern United States. Its larva is commonly known as the ailanthus silkworm, while the yamamai and pernyi silkworms are commonly known as oak silkworms.
The yama-mai silkworm is commonly raised in Japan and its cocoon is large, heavy, and hand some, and of a yellowish-green color. It is readily reeled, and its silk ranks commercially next to that of the domestic silkworm. The silk is strong and valuable. It bleaches well and may then be dyed. Fewer threads are required to make a strand than with Bombyx mori, and the cocoons unwind with perfect ease by the ordi nary process. The life of the worm lasts from 50 to 80 days, and it feeds on all kinds of oak. but prefers those of the white oak group.
The pernyi silkworm has been cultivated in Europe with better success than the yamamai. It develops more rapidly, is double-brooded, and passes the winter in the chrysalis state. The cocoon is not so valuable, though ranking proba bly third best among the different silkworm cocoons.
The ailanthus silkworm is utilized extensively in North China. It has been known in Europe since the middle of the last century, and has been cultivated there as well as in the United States with perfect success. The cocoons, how
ever, cannot he reeled successfully, and their silk is utilized principally by carding processes.
In the United States several species of silk worm moths occur, and their caterpillars spin an abundance of silk of a strong and durable quality. The 'American' silkworm (Telco, Poly phemus) is a large moth of a buff color, whose caterpillar feeds upon the leaves of many trees. including oak, willow, hickory, maple, apple, sycamore, and many others. The cocoon is formed of strong silk, which when unwound has a glossy fibre. It is oval and closed at both ends, dense, and generally fastened to a leaf or leaves with which it sometimes falls to the ground. The fibres are intermixed and cemented with a gummy substance which when dry gives the cocoon a chalky appearance. The principal difficulty in reeling the cocoon is in the hard matter which binds the threads. This, however. may be softened, and no doubt the cocoon could be improved by a process of continued selection. The insect has one generation each year in the Northern States and two in the Southern States, and passes the winter in the chrysalis state.
The large lung moth (Troptra lena) is a beau tiful species of a delicate green color, with long tails to the hind wings, whose larva feeds on several forest trees and whose cocoon is less dense than that of the Polyphemus moth. The cocoons of these two species have the same gen eral characteristics as those of the yamamai silk worm. Another native North American silkworm (Callosamia promethia) resembles in many re spects the ailanthus worm. Its cocoon. like that species, is open and is in the same way difficult to reel. It feeds on ash, sassafras, wild cherry. maple, lilac, birch, and other trees. The largest of the American silkworms is the larva of Sarnia cecropia, a beautiful moth of a grayish brown color marked with reddish and yellowish spots and bands. The large green larva, which bears six coral-red tubercles on its thorax and smaller blue tubercles on its abdomen, feeds upon the apple and other rosaceous plants, as well as upon hazel, hickory, maple, willow, and honey-locust. The cocoon is peculiar in being apparently double. There is a thick, wrinkled outer layer which re sembles strong brown paper and which covers an inner oval cocoon composed of the same kind of silk, but closely woven like that of the mulberry silkworm. Nearly related to this species are Sarnia Olor(ri, of the floeky Mountain region; Sarnia columba, of the North Atlantic States; and Sarnia rubra, from the Pacific States. In Mexico there arc several large silkworm moths of the Saturnian group which produce quantities of silk, but it has not been commercially utilized or experimented with. There is another group of moths belonging to the family Psychithe, in which the larva makes a large bag of silk which it car ries about with it to protect its soft body from the attacks of birds. A common American ex ample is the bagworm (q.v.) or basket-worm. This silk has not been utilized except in China.