282 INSECTS INJURIOUS TO VEGETATION. 



The Luna, Polyphemus, Cecropia, and Promethea moths are 

 the only native insects belonging to the genus Attacus which are 

 known to me. Their large cocoons, consisting entirely of silk, 

 the fibres of which far surpass those of the silk-worm in strength, 

 might perhaps be employed in the formation of fabrics similar to 

 those manufactured in India from the cocooiis of the tusseh and 

 arrindy silk- worms, the durability of which is such, that a garment 

 of tusseh silk "• is scarcely worn out in the lifetime of one person, 

 but often descends from mother to daughter ; and even the cov- 

 ers of palanquins made of it, though exposed to the influence of 

 the weather, last many years." The method, employed by the 

 inhabitants of India for unwinding the cocoons of their native silk- 

 worms, would probably apply equally well to those of our coun- 

 try, which have not yet, that I am aware of, been submitted to the 

 same process. It is true that experiments, upon a very limited 

 scale, have been made with the silk of the Cecropia, which has 

 been carded and spun and woven into stockings, that are said to 

 wash like linen. The Rev. Samuel Pullein was among the first 

 to attempt to unwind the cocoons of the Cecropia moth, an ac- 

 count of which is contained in the "Philosophical Transactions 

 of the Royal Society of London" for the year 1759*. Mr. Pul- 

 lein ascertained that twenty threads of this silk twisted together 

 would sustain nearly an ounce more in weight than the same num- 

 ber of common silk. jyir. Moses Bartram, of Philadelphia, in the 

 year 1767, succeeded in bringing up the caterpillars from the 

 eggs of the Cecropia moth, and obtained several cocoons from 

 themf. In the Paris " Journal des Debats," of the twenty- 

 third of July, 1840, is an account of the complete success of Mr. 

 Audouin, in rearing the caterpillars of this or of soma other 

 American species of Attacus, the cocoons of which were sent to 

 him from New Orleans. The Cecropia does not bear confine- 

 ment well, and is not so good a subject for experiment as the 

 Luna and Polyphemus, which are easily reared, and make their 

 cocoons quite as well in the house as in the open air. The fol- 



* Vol. LI., p. 54. 



t See " Transactions of the American Philosophical Society of Philadelphia," 

 Vol. 1., p. 2U4. 



