144 NORTH AMERICAN INSECTS. 



Southern States could do the same with negro children, as 

 well as with the old men and women who have become in- 

 capacitated for hard work. 



To plant a large number of white mulberry-trees, for the 

 purpose of raising silk-worms, is neither difficult nor expens- 

 ive, and whoever raises a large quantity of cocoons may be 

 sure of a ready cash sale of them, and at a great profit. 



All the silk and silk-stuffs of commerce originate from 

 the common silk- worm ; but there exist several other species 

 of nocturnal lepidoptera in America and in Asia, which 

 produce silk of a difierent kind, of which no use, or a very 

 limited one, is made ; as, for instance, that of the Bomhyx 

 madrono, mentioned in Humboldt's travels, which is found 

 in the province of Mechoacau, in Mexico, at the height of 

 10,500 feet above the level of the sea. Handkerchiefs are 

 manufactured of this silk by the inhabitants of Oaxaca. 



The cocoons of the large North American Moths, Cecro- 

 pia, Luna, Polyphemus, and Promethea, which I shall il- 

 lustrate hereafter, contain much silk, a single fibre of which 

 is at least ten times as thick as one of the common silk- 

 worm — an experiment I have often made myself Stuffs 

 made out of this silk would far exceed the common fabrics 

 in strength and durability, and could not, probably, be worn 

 out in many years. 



In India silk is also obtained from the cocoons of other 

 Moths, in relation to which Kirby and Spence say : " Of 

 these, the most important species known are the Tusseh and 

 Arindy Silk-worms. These insects are both natives of 

 Bengal. The first {Attacus impilio, Linn.), feeds upon the 

 leaves of the jujube-tree, or Byer of the Hindoos, and upon 

 the Terminalia alata glabra, Roxb., the Asseen of the Hin- 

 doos, and is found in such abundance as from time imme- 

 morial to have afforded a constant supply of a very durable, 

 coarse, dark-colored silk, which is woven into a cloth called 

 Tusseh-doothies. This fabric is much worn by the Brah- 



