ON SERICICULTURE. 113 



the experiment has quite failed. The silk is said to be of 

 good quality and to reel off easily, and 1,500 yards are fur- 

 nished by a single cocoon. 



B. Cecropia, a very handsome insect, produces the largest 

 cocoon, of a strong coarse silk, more suitable for carding 

 than for reeling purposes. The worm is at first black, then 

 yellow and black, but after its third moult assumes a lovely 

 blue-green hue, and when full grown is a fine and very 

 handsome larva, with red and yellow tubercles. It is easily 

 reared, and is likely to prove a favourite with schoolboys, 

 and those who are fond of rearing handsome larvae. I possess 

 a fair store of cocoons reared on apple last summer. 



Lastly, B. Promethea, producing a cocoon smaller but 

 exactly similar to that of ^. Cynthia, is not a likely insect 

 to be introduced into England, as its food plant is not indi- 

 genous, and the silk and insect are both inferior to B. 

 Cynthia and its product. I may mention a peculiarity of 

 this insect, — that of the few cocoons sent to me, the greater 

 part of them were males ; that they flew about in the after- 

 noon from three to five ; and that the only pair I had copu- 

 lated during that period, and the $ laid her eggs the same 

 night. 



In attempting to introduce and acclimatize new silkworms 

 two points must be observed to attain any chance of success: 

 1. That the insect experimented upon should be introduced 

 to a climate and temperature similar to that of the country 

 of which it is a native ; 2. That its food plant should be 

 indigenous and easily procurable in large quantities. Given 

 these data, we may set about the experiment with a fair hope 

 of success. Other conditions are however necessary in a 

 commercial point of view, viz., that the cocoons should 

 be produced in large quantity, be easily converted into 

 silk, and be of a sufficient value to remunerate amply the 

 1869. I 



