85 
THE AMERICAN SILK WORM. 
BY L. TROUVELOT. 
Oe 
(Continued from page 38.) 
It is astonishing how rapidly the larva grows, and one 
who has no experience in the matter could hardly believe 
what an amount of food is devoured by these little crea- 
tures. One experiment which I made can give some idea 
of it: when the young silk worm hatches out, it weighs 
one-twentieth of a grain; when 
we days old it it weighs sa grain, or D times the original weight. 
: grains ‘‘ 
30 ae ae ae ac 81 és Ls 620 “ ae ¿t “ 
40 ét it ae “es 90 ae ce 1800 “ce ae i “ 
56 ac se ae ee 207 ae ét 4140 ae é 4 
When a worm is thirty days old it will have aE 
about ninety grains of food; but when fifty-six days old 
it is fully grown and has consumed not less than one hun-. 
dred and twenty oak 
leaves weighing three- 
fourths of a pound; 
besides this it has 
drank not Jess than 
one-half an ounce of 
water. So the food 
taken by a single silk Cocoon of Tela Polyphemus. a E 
worm in fifty-six days equals in weight eighty-six thou- 
sand times the primitive weight of the worm. Of this, 
about one-fourth of a pound becomes excrementitious 
matter; two-hundred and seven grains are assimilated 
and over five ounces have evaporated. What a destruction 
of leaves this single species of insect could make if only a 
one-hundredth part of the eggs laid came to maturity! A 
few years would be sufficient for the propagation of a num- 
ber large enough to devour all the leaves of our forests. 
