"The Polyphemus worm spins a strong, dense, oval cocoon, which is closed at each end, while the silk has a very strong and glossy fibre." Mr. Trouvelot, from whose interesting account in the first volume of the "American Naturalist" we quote, says that in 1865 "not less than a million could be seen feeding in the open air upon bushes covered with a net; five acres of woodland were swarming with caterpillar life." The bushes were scrub oaks, the worms being protected by a net. After meeting with such great success Mr. Trouvelot lost all his worms by pebrine, the germs being imported in eggs received from Japan through M. Guerin-Meneville of Paris. Enough, however, was done to prove that silk raising can be carried on profitably, when due precautions are taken, as far north as Boston. As this moth extends to the tropics, it can be reared with greater facility southwards. The cocoon is strong and dense, and closed at each end, so that the thread is continuous, while the silk has a very strong and glossy fibre. [Illustration: 54. American Silk Worm.] Next in value to the American silk worm, is the Ailanthus silk worm (Samia Cynthia) a species allied to our Callosamia Promethea. It originated from China, where it is cultivated, and was introduced into Italy in 1858, and thence spread into France, where it was introduced by M. Guerin-Meneville. Its silk is said to be much stronger than the fibre of cotton, and is a mean between fine wool and ordinary silk. The worm is very hardy, and can be reared in the open air both in this country and in Europe. The main drawback to its culture is the difficulty in unreeling the tough cocoon, and the shortness of the thread, the cocoon being open at one end. The Yama-mai moth (Antheraea Yama-mai) was introduced into France from Japan in 1861. It is closely allied to the Polyphemus moth, and its caterpillar also feeds on the oak. Its silk is said to be quite brilliant, but a little coarser and not so strong as that of the Bombyx mori. The Perny silk worm is extensively cultivated by the Chinese in Manchouria, where it feeds on the oak. Its silk is coarser than that of the common silk worm, but is yet fine, strong and glossy. Bengal has furnished the Tussah moth, which lives in India on the oak and a variety of other trees. It is largely raised in French and English India, according to Nogues, and is used in the manufacture of stuffs called corahs. [Illustration: 55. Chrysalis of American Silk Worm.] [Illustration: 56. Cocoon of American Silk Worm.] The last kind of importance is the Arrhindy silk worm, from India. It has been naturalized in France and Algeria by M. Guerin-Meneville, who has done so much in the application of entomology to practical life. It is closely allied to the Cynthia or Ailanthus worm, with the same kind of silk and a similar cocoon, and feeds on the castor oil plant.