302 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 for- 

 mation of fabrics similar to those manufactured in India from 

 the cocoons of the tusseh and arrindy silk worms, the dura- 

 bility 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 covers 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 

 country, which have not yet, that I am aware of, been sub- 

 mitted 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 account of which is contained in the 

 " Philosophical Transactions of the Royal Society of London," 

 for the year 1759.* Mr. Pullein ascertained that twenty threads 

 of this silk twisted together would sustain nearly an ounce 

 more in weight than the same number of common silk. Mr. 

 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 them.f 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 some other American species of 

 Attacus, the cocoons of which were sent to him from New 

 Orleans. The Cecropia does not bear confinement well, and 

 is not so good a subject for experiment as the Luna and Poly- 



* Vol. LI., p. 54. 



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

 Vol. I., p. 294. 



