THE AMERICAN ENTOMOLOGIST. 



tenacious gluten, for which reason it has 

 never been successfully unwound, and even 

 carding is not an easy operation. Like 

 that of our Cecropia, the Ailanthus cocoon 

 is open at one end, and though the thread 

 is continuous, and if disengaged of the 

 glutinous matter which binds it, may be 

 continuously reeled off, yet such reeling is 

 rendered difficult from the fact that the 

 moment the cocoons are placed in the ba- 

 sin they fill with water, sink to the bottom, 

 and cause the threads to continually break. 



There are some important facts connected 

 with ailanthus silk which recommend it. 

 It bleaches well, and has long been used 

 in China, where it is known to be so durable 

 that a dress made from it frequently de- 

 scends as an heir loom for generations. It 

 has for many years been in the markets of 

 France, and specimens of manufactured 

 staffs from it, which we saw in Paris and 

 London, took on sundry dark colors very 

 well and looked remarkably fine. 



This class of goods is known as Ailan- 

 tiiie, and might be put to a great many uses, 

 as there is always a demand for coarse 

 silks. We have understood that specimens 

 of this silk have been successfully woven 

 at Paterson, N. J. 



A number of devices for unwinding the 

 cocoons have been patented in Europe, 

 but none seem to have come into general 

 use, and whatever impetus they may give 

 ailanti-cwliwre;, we may rest perfectly satis- 

 fied that such culture will never become 

 general, and that the Ailatithus silkworm 

 will never replace that of the Mulberry. 



The prime reason why the Mulberry 

 silkworm must ever be the silk producer 

 of commerce, aside from the superior qual- 

 ity and quantity of its silk, is that it is a 

 domesticated insect, and that the worm 

 can be fed in large quantities in partial 

 confinement and under control ; further, 

 that, while enduring this artificial life, it 

 shows no disposition to escape from the 

 shallow trays upon which it is fed. All 

 the other worms suffer more or less when 

 brought together in large numbers, or 

 when confined or sheltered, and in this fact 

 more than in any difficulty in using the 



silk, lies the secret of the failure to substi- 

 tute any of them for mori. The hardiness 

 and adaptability of cynthia to different cli- 

 mates cannot offset this objection ; for it 

 remains essentially a wild worm, and it 

 will require many centuries of selecting 

 and artificial rearing ere it can be domes- 

 ticated to the same extent that is the Seri- 

 cai'ia mori. There never can be any de- 

 pendence placed on the production of silk 

 from worms growing wild on their food- 

 plants, as in such state their exposure to 

 birds and other enemies will always render 

 the cocoon harvest uncertain, and it is far 

 more expensive and troublesome to pro- 

 tect both the wild worms and the trees on 

 which they grow, than it is to rear the 

 Mulberry worm by the ordinary methods 

 employed. 



The question of cultivating our Attacus 

 cecropia is again being discussed in France. 

 Its silk is less valuable than that of cynthia, 

 and all the objections to this last apply 

 still more forcibly to cecropia. The fol- 

 lowing conclusions which we came to in 

 1 87 1,* after considering all the introduced 

 and native silkworms of any importance, 

 hold equally true to-day : 



There can be no good .reason given why .silk- 

 culture ma}' not become one of the industries of 

 this country, especially if fostered at the start. 

 We would, however, advise no one to enter into 

 it on a large scale, as a business. The raising of 

 silk is seldom lucrative, even in the most favor- 

 able countries ; for in this as in most other in- 

 dustries, the principal profits accrue to the mid- 

 dlemen, reelers, and manufacturers ; but on a 

 small scale, and prosecuted in connection with 

 other branches of agriculture and horticulture, 

 it will give most desirable returns for the time 

 employed. The erection of a few reeling estab- 

 lishments is absolutely necessary to establish 

 this industry. 



For in-door culture, no worm surpasses the 

 mulberry species {mori), for out-door culture none 

 at present surpass the ailanthus species {cynthia), 

 though \i yama-ntai and />er/iyi can once be accli- 

 mated, their cocoons are more valuable. Of the 

 native worms polypheiiius is the most valuable 

 and important, its silk being easily reeled and of 

 excellent quality : cecropia comes next in order, 

 its silk being reeled with difficulty, while that of 

 proiiu-thea and luna is of less value, has never yet 

 been, and probably cannot be reeled. 



The Hickory Scolytus (-5". ^-spinosus Say), 

 has recently been received from Wash. Ter., 

 showing that this pest is more widely dis- 

 tributed than heretofore supposed. 



* 4th Mo. Ent. Rep., p. 



