

THE CYNTHIA SILK-WORM. 313 
But the principal objection to the American silk-moths is, 
tha: they produce only one brood a year, with the exception, 
I believe, of Luna. Now the Cynthia can be made to pro- 
duce two broods easily; and, so far as I can see, the cocoon 
of the second brood is just as good as that of the first. Again, 
the food of some of the species is of very slow growth; such 
as the oak, the elm, and the hickory. 
Now the food of the Cynthia, at least in this country, is ` 
the ailanthus, a tree of luxuriant foliage and rapid growth; 
and, at present, more ornamental than useful. If we accli- 
matize the Oynthia, we can reverse the order of things. It 
is somewhat doubtful, for reasons I shall presently give, 
whether the ailanthus is the natural food of this insect; but 
I will waive that consideration for the present. 
In view of the confusion which evidently exists as to the 
identity of Cynthia, I think it best here to state, that the 
insect I am writing about is the one figured, tolerably well, 
m Dunean’s Exotic Moths, Plate 14, fig. 1. The coloring 
there is not quite correct, but that is, doubtless, the moth. ` 
Drury (Westwood’s edition) has also given a tolerably 
Accurate figure in his “ Illustrations,” and taking (as every 
body else seers to have taken) his description from that of 
Dr, Roxburgh’s Memoirs on the Silk-producing Moths of 
the East (Transactions of the Linnean Society, Vol. 7), 
calls it the “Arrindy Silk-worm ;” says that it feeds on the 
“'stor-oil plant, and that its soft cocoons are so delicate and 
Jossy, that it is impossible to wind them off, and that there- 
fore they are spun like cotton. Now this description, which 
' substantially quoted by Mr. A. R. Grote in the “Practical 
htomologist,” by no means applies to the cocoon of the 
ynthia. It is not a soft, flossy cocoon, like that of Cecro- 
but hard like that of Promethea, which indeed it gene- 
Y resembles. There is, to me, certainly a difficulty in 
Sit; and this, at present, is the main objection to it. 
ha ifficulty arises from our ignorance of the proper 
ents for the gum of the cocoon, and the proper temper- 
CMER. NATURALIST, VOL. 11. : 
