THE AMERICAN SILK WORM. 89 
sure twenty five inches in length; these two reservoirs 
become very narrow as they approach the mouth, and 
unite together, terminating in a special contractile organ, 
attached beneath the mouth. When spinning, the silk is 
thrown out from the two reservoirs at the same time, and 
the thread is in reality composed of two distinct fibres 
which can be easily separated. 
The silk in the reseryoirs is sometimes used in com- 
merce, being sold under the name of “gut.” The pro- 
cess of obtaining the gut is very simple; it consists in 
preparing worms ready to spin by putting them in strong 
vinegar for eighteen hours; a transverse opening is then 
carefully made on the under side and about the middle of 
the body, taking care not to injure the silk reservoirs 
which are very distinct. The glands, or reservoirs, are 
then taken out and stretched parallel to each other on a 
board, and dried in the shade for several days. 
The Enemies of the Silk Worm. Birds are the most 
formidable foes to the silk worm, especially the Thrushes, 
. Cat-birds and Orioles. It 
is probable that ninety-five 
out of a hundred worms 
eat the chrysalis enclosed 
within the cocoon. Among 
insects they have many 
enemies, such as various 
spiders, ants, bugs and 
sargoria Linn. Ichnenmon Parasite : 
“wasps; but their most n the larva of Telea Polyphemus 
AMERICAN NAT. VOL. I. 12 
