220 REPORT OF THE COMMISSIONER OF AGRICULTURE. ¥ 
The color of the newly hatched worm is black or dark gray, and it is 
covered with long stiff hairs, which, upon close examination, will be 
found to spring from pale-colored tubercles. Different shades ‘of dark 
gray will, however, be found among worms hatching from the same 
batch of eggs. The hairs and tubercles are not noticeable after the first 
molt, and the worm gradually gets lighter and lighter until, in the last age, 
it is of a cream-white color. When full grown it presents the appear- 
ance of Fig. 1, Pl. I. It never becomes entirely smooth, however, as 
there are short hairs along the sides, and very minute ones, not notice 
able with the unaided eye, all over the body. 
The preparation for each molt requires from two to three days of fast- 
ing and rest, during which time the worm attaches itself firmly by the 
abdominal prolegs (the 8 non-articulated legs under the 6th, 7th, 8th and 
9th segments of fhe body, called prolegs in contradistinction to the 6 
articulated true legs under the ist, 2d, and 3d segments), and holds up 
the fore part of the body, and sometimes the tail. In front of the first — 
joint a dark triangular spot is at this time noticeable, indicating the 
growth of the new head; and when the term of ‘‘sickness” is over the 
worm casts its old integument, rests a short time to recover strength, 
and then, freshened, supple, and hungry, goes to work feeding vora- 
ciously to compensate for lost time. This so-called “sickness” which 
preceded the molt, was, in its turn, preceded by a most voracious appe- 
tite which served to stretch the skin. In the operation of molting the 
new head is first disengaged from the old skin, which is then gradually 
worked back from segment to segment until entirely cast off. If the 
worm is feeble, or has met with any misforture, the shriveled skin may 
remain on the end of the body, beimg held by the anal horn; in which 
case the indvidual usually perishes in the course of time. It has been 
usually estimated that the worm in its growth consumes its own weight 
of leaves every day it feeds; but this is only an approximation. Yet it 
is certain that during the last few days before commencing to spin, it 
consumes more than during the whole of its previous worm existence. 
It is a curious fact, first noted by Quatrefages, that the color of the ab- 
dominal prolegs at this time corresponds with the color of the silk. 
Having attained full growth the worm is ready tospinup. It shrinks 
somewhat in size, voids 1 most of the excrement remaining in the alimen- 
tary canal; acquires a clear, translucent, often pinkish or amber-colored 
slant) becomes restless; ceases to feed, and throws out silken threads. 
The silk is elaborated in a fluid condition in two long, slender, eonyo- 
luted vessels, one upon each side of the alimentary canal. As these 
vessels approach the head they become less convoluted and more slen- 
der, and finally unite within the spinneret from which the silk issues in 
a glutinous state and apparently in a single thread. The glutinous 
liquid which combines the two, and which hardens immediately on ex- 
posure to the air, may, however, be dissolved in warm water. The worm 
usually consumes from three to five days in the construction of the 
cocoon, and then passes, in three days more, by a final molt, into the 
chrysalis state. 
THE Cocoon (PI. I, Fig. 2).—The cocoon consists of an outer lining 
of loose silk, known as “floss,” which is used for carding, and is spun 
by the worm in first getting its bearings. The amount of this loose 
silk varies in different breeds. The inner cocoon is tough, strong, and 
compact, composed of a firm, continuous thread, which is, however, not 
wound in concentric circles as might be su pposed, but irregularly, in 
short figure of 8 loops, first in one place and then in another, so that in 
reeling several yards of silk may be taken off without the cocoon turn- 
