152 



NORTH AMERICAN INSECTS. 



About twenty years ago the business of raising silk- 

 worms was extensively introduced throughout the United 

 States, and was entered into with great enthusiasm, but so 

 foolishly, and with so little knowledge of the subject, that 

 the Morus Multicaulis speculation proved an entire failure, 

 and caused almost an abandonment of this branch of indus- 

 try. The changeable temperature of the Northern, Eastern, 

 and Middle States renders them naturally less suitable for 

 the cultivation of the white mulberry, at the time when its 

 leaves are most needed for the young silk-worms, than the 

 Southern States, and, besides, manual labor costs more in 

 the North than in the South, where all the work of a, silk 

 establishment may be performed by superannuated or very 

 young slaves, no physical strength being necessary for super- 

 intending the silk-worms or for unwinding their cocoons. 

 Since the Morus Multicaulis fever died away, however, very 

 few silk-worms have been raised in this country, as may 

 be seen from the Statistical View of the United Slates, ly J. 

 D. B. De Bow, Superintendent of the United States Census, 

 Washington, 1854 ; from which I copy the following table : 



SILK COCOON PRODUCTION OF THE UNITED STATES IN 1840 AND 

 1850. 



