ll-t FOURTH ANNUAL REPORT OF 



erations. In confirmation of the statement that the cocoons in Enghxnd 

 were remarkable for their size, M. de Roo van Westmas, writing from the 

 Netherlands, a moister and more temi^erate clime than France, in August, 

 1864, says "The acclimatization of B. Cyntliia has perfectly succeeded, and 

 presents a remarkable fact, viz., that the race is, without doubt, ameliorated. 

 The moths are larger and more vigorous than those of the preceding year. 

 The females laid last year from 100 to 150 eggs, but now give from 300 to 

 350, and what is still more remarkable is, that the eggs are larger and heav- 

 ier, for whereas before a gramme contained 540 — 560, now I find only 440 — 460 

 in that weight; this fact appeared to me of such importance that I counted 

 the eggs in five grammes taken from a weight of thirty grammes. I found 

 the number 2261 which gives an average of 452 eggs to a gramme." A 

 gramme being equal to 152 grains (nearly), this gives twenty-nine or thirty 

 eggs to the grain. My own experience tallies exactly with that of Mr. de 

 Eoo ; specimens bred in 1865, the progeny in part of French eggs pur- 

 chased in 1863, exhibited as the result of two years' acclimatization in Eng- 

 land a marked imj^rovement in size, color, etc., in all their stages, as con- 

 trasted with their French progenitors, and the cocoons were finer in 1865 

 than in 1864. Lady Dorothy Xevill also reports that the English eggs and 

 cocoons are finer than the French. If this be proved b}^ further observa- 

 tion it becomes an important argument in favor of English Ailanthiculture, 

 for a larger cocoon implies a greater weight of silk. 



WHEN INTRODUCED INTO AMERICA. 



In 1861 the Ailanthus worm was introduced into this country, the credit 

 of which is due to Dr. Thomas Stewardson of Philadelphia, Pa. Two able 

 and interesting papers on the subject were published by Dr. J. Gr. Morris of 

 Baltimore, Md., in the Agricultural Reports for 1861 and 1862, great hopes 

 being entertained as to the success of the new enterprise. 



Since that time the insect has been raised by a great many ditfcreut 

 persons in the United States, and has been fully ox])erimented with. In the 

 summer of 1865 I gave it a very thorough trial at Chicago, and raised large 

 quantities both indoors and on trees in the open air; and the following par- 

 agraphs from an article which was published in the Prairip Farmer of April 

 28th, 1866, will serve to illustrate its real -value : 



I raised two broods last summer without difficulty, the last w^orm of the 

 second brood having spun on the 23d September. Not one died, either of 

 those raised in doors or out on the trees exposed to the weather, except by 

 accident or from the attacks of birds. 



So, therefore, as regards hardiness and adaptibility to our climate there 

 is little question of its merit, there being few places on our continent sub- 

 ject to more sudden changes and extremes of temperature than Chicago j 

 but in an economical point of view, the sanguine expectation of its advo- 

 cates have not been realized, and notwithstanding the furore which it at 

 first occasioned in France and the much that has been said in its favor b}' 

 our Commissioner of Agriculture,* it never will take the place of the Mul- 

 berry Silkworm, and M. E. P. Guerin-Meneville is at this day making re- 

 searches for, and experimenting with other worms, and has lately laid 

 before the Academy of Sciences, Paris, a species of Bombyx {Anthercea) which 

 was obtained on the frontier of Cashmere and feeds on an Oiik,{Quercus in- 

 cand). 



The Ailanthus worm has two rather serious disadvantages. The cocoon 



* Isaac Newton was ijicumbeiit at that time. 



